Merge remote-tracking branch 'origin/master' into codex/status-bar-token-metrics

# Conflicts: # apps/web/tests/snapshots/code-mode-round/ui.expected.md # apps/web/tests/snapshots/cordis-tool-round/ui.expected.md # apps/web/tests/snapshots/fresh-round-trip/ui.expected.md # apps/web/tests/snapshots/lifecycle-chrome/reloaded.expected.md # apps/web/tests/snapshots/live-interactions/cancel.expected.md # apps/web/tests/snapshots/live-interactions/retry.expected.md # apps/web/tests/snapshots/seeded-history/ui.expected.md # apps/web/tests/snapshots/steering/mid-steer.expected.md # apps/web/tests/snapshots/steering/settled.expected.md # packages/client/ui-conversation/README.i18n.yaml
2026-07-29 15:36:38 +08:00
parent bf618dabf9 59ecfac776
commit d20e531153
63 changed files with 1111 additions and 246 deletions
--- a/.agents/notes/implemented/bug-fix/2026-07-29-web-details-session-lifecycle.i18n.yaml
+++ b/.agents/notes/implemented/bug-fix/2026-07-29-web-details-session-lifecycle.i18n.yaml
@@ -0,0 +1,6 @@
+# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
+# side as of the last confirmed-consistent state. Both languages carry equal authority;
+# after editing either side, bring the other along and re-record with:
+#   pnpm run verify-translation-pairing --write .agents/notes/implemented/bug-fix/2026-07-29-web-details-session-lifecycle.md
+2026-07-29-web-details-session-lifecycle.md: d9e0255768f165bed0631b9324e971b57ec7dcae
+2026-07-29-web-details-session-lifecycle.zh.md: 09452ba80ff240ddca76df239b40ea661566f8e2
--- a/.agents/notes/implemented/bug-fix/2026-07-29-web-details-session-lifecycle.md
+++ b/.agents/notes/implemented/bug-fix/2026-07-29-web-details-session-lifecycle.md
@@ -0,0 +1,29 @@
+# Agent Note: Web details follow the current Session lifecycle
+
+Status: implemented
+
+English | [中文](2026-07-29-web-details-session-lifecycle.zh.md)
+
+## Problem
+
+The details entry is Session-scoped, but its preferred grid width is root-scoped. Selecting a different Session replaced the details content without closing that root preference, so the new owner inherited stale viewing geometry. Hero and other unselected states render no Session-scoped details; they need a derived zero track without becoming false owners in the comparison.
+
+## Decision
+
+`AppFrame` reads the current Session id and its `blank` summary flag from the authoritative Session projection. It records the last non-blank selected id only when that Session can own details, so hero and other unselected states neither trigger closure nor replace the last Session owner; their rendered details track derives as zero without changing the stored preference. The first Session keeps the default details width; returning to the same Session restores its current width; selecting a different Session closes the root-scoped details preference through the layout store before paint. The per-Session chat selection remains owned by the session-scoped store described by the [slot system standard](../architecture/2026-07-22-slot-type-chain-implementation.md).
+
+The layout store is transient and starts details at its default width. It neither reads nor writes `localStorage`, so reload resets both panel widths and needs no Session-baseline exception. Manual close and reopen inside one unchanged Session retain their existing behavior. The lifecycle effect changes neither the [Workspace-owned New Session flow](../feature/2026-07-25-workspace-ui-product-flow.md), composer drafts, Session navigation, nor concession-chain resizing.
+
+## Alternatives considered
+
+**Close details in the New Session click handler.** Rejected because an unselected surface has no Session-scoped details and must not mutate geometry. Closure belongs to the later comparison between two defined Session owners.
+
+**Persist panel geometry per Session.** Rejected because the product contract needs stale context removed, not a new map of remembered widths. Per-Session geometry would also reopen details when users return, contrary to the chosen close-on-leave behavior.
+
+**Preserve persisted layout after the Session baseline is ready.** Rejected because it duplicates startup lifecycle in a presentation component solely to validate stale viewing state. Transient defaults make reload deterministic without a readiness flag.
+
+**Treat every current-projection change as a Session switch.** Rejected because startup materialization, hero, clearing selection, and invalidation are not transitions between two Session owners.
+
+## Consequences
+
+Details is open by default, including when the first Session materializes. Switching to a different Session forgets the dragged details width because close writes zero and reopen uses the contract default. Unselected states derive a zero rendered track while leaving the preferred geometry unchanged; returning to the same Session through one of those states restores its width. Reload forgets sidebar and details geometry. The layout behavior test covers initial defaults, first materialization, direct and hero-mediated Session switches, same-Session return, and the absence of layout storage; the keyless browser e2e drives the same owner transitions through the shipped composition while checking the full grid track and browser errors.
--- a/.agents/notes/implemented/bug-fix/2026-07-29-web-details-session-lifecycle.zh.md
+++ b/.agents/notes/implemented/bug-fix/2026-07-29-web-details-session-lifecycle.zh.md
@@ -0,0 +1,29 @@
+# Agent Note: Web 详情栏遵循当前会话生命周期
+
+Status: implemented
+
+[English](2026-07-29-web-details-session-lifecycle.md) | 中文
+
+## 问题
+
+详情入口由会话作用域拥有，而其首选网格宽度由根作用域拥有。选择不同会话时，系统会替换详情内容，却不会关闭根作用域的该首选宽度，因此新 owner 会继承陈旧的查看几何信息。hero 和其他未选中状态不会渲染会话作用域的详情；其轨道需派生为零宽度，但不能因此在比较中成为伪 owner。
+
+## 决策
+
+`AppFrame` 从权威会话投影读取当前会话 id 及其摘要中的 `blank` 标志。它只在该会话能够拥有详情时记录最后一个选中的非 blank 会话 id，因此 hero 和其他未选中状态既不会触发关闭，也不会替换最后一个会话 owner；这些状态下，详情栏轨道的渲染宽度派生为零，但存储的首选宽度不变。首个会话保留详情栏的默认宽度；返回同一会话时恢复其当前宽度；选择不同会话时，系统会先通过布局 store 关闭根作用域存储的详情栏首选宽度，再进行绘制。逐会话的聊天选中项继续由 [slot 体系标准](../architecture/2026-07-22-slot-type-chain-implementation.md)所述的会话作用域 store 拥有。
+
+布局 store 是瞬时状态，详情栏以默认宽度启动。它既不读取也不写入 `localStorage`，因此重新加载会重置两个面板的宽度，无需会话基线例外。在同一个未变化的会话内手动关闭和重新打开详情栏，仍保持原有行为。该生命周期 effect 不改变 [Workspace 拥有的 New Session 动线](../feature/2026-07-25-workspace-ui-product-flow.md)、composer 草稿、会话导航或让步链缩放。
+
+## 考虑过的替代方案
+
+**在 New Session 点击处理器中关闭详情栏。** 之所以否决：未选中表面没有会话作用域的详情，不得修改几何信息。详情栏是否关闭，应由随后对两个已定义会话 owner 的比较决定。
+
+**按会话持久化面板几何信息。** 之所以否决：产品契约需要移除陈旧上下文，而不是新增一张保存各宽度的映射。按会话保存几何信息还会在用户返回时重新打开详情栏，与选定的离开即关闭行为相悖。
+
+**在会话基线就绪后保留持久化布局。** 之所以否决：这会仅为验证陈旧的查看状态，在呈现组件中重复实现启动生命周期。瞬时默认值无需就绪标志即可使重新加载具有确定性。
+
+**将当前投影的每次变化都视为会话切换。** 之所以否决：启动时的物化、hero、清除选中项和选中状态失效都不是两个会话 owner 之间的过渡。
+
+## 后果
+
+详情栏默认打开，首次会话物化时亦然。切换到不同会话会忘记拖动后的详情宽度，因为关闭操作会写入零值，重新打开时则使用契约默认值。未选中状态会将轨道的渲染宽度派生为零，同时保持首选几何信息不变；经由这些状态返回同一会话时，会恢复其宽度。重新加载会忘记侧边栏与详情栏的几何信息。布局行为测试覆盖初始默认值、首次物化、直接及经 hero 中转的会话切换、返回同一会话，以及不存在布局存储的情况；无密钥浏览器 e2e 则通过已交付的组合驱动相同的 owner 过渡，同时检查完整网格轨道和浏览器错误。
--- a/.agents/notes/implemented/feature/2026-07-29-web-message-icon-actions-and-clock.i18n.yaml
+++ b/.agents/notes/implemented/feature/2026-07-29-web-message-icon-actions-and-clock.i18n.yaml
@@ -0,0 +1,6 @@
+# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
+# side as of the last confirmed-consistent state. Both languages carry equal authority;
+# after editing either side, bring the other along and re-record with:
+#   pnpm run verify-translation-pairing --write .agents/notes/implemented/feature/2026-07-29-web-message-icon-actions-and-clock.md
+2026-07-29-web-message-icon-actions-and-clock.md: e0072458e4c0d3e37998b5564ad14ce17aa41515
+2026-07-29-web-message-icon-actions-and-clock.zh.md: 1cc25a9656e7a100d78dd3b6b3675ca490f455f9
--- a/.agents/notes/implemented/feature/2026-07-29-web-message-icon-actions-and-clock.md
+++ b/.agents/notes/implemented/feature/2026-07-29-web-message-icon-actions-and-clock.md
@@ -0,0 +1,27 @@
+# Agent Note: Web message IconActions and clocks
+
+Status: implemented
+
+English | [中文](2026-07-29-web-message-icon-actions-and-clock.zh.md)
+
+## Problem
+
+The web chat user bubble already had copy / branch / edit IconActions but no clock. Finalized assistant narration had no under-body action chrome at all, even though the Harness design shows a copy / branch / clock row after the answer settles. Streaming replies must not flash that chrome mid-token. Memoized rows also keep stable props across midnight, so a one-shot `Date.now()` would leave yesterday's messages stuck on `HH:mm`.
+
+## Decision
+
+**User bubbles prepend a date-aware local clock to the existing IconActions row; finalized assistant nodes append a copy / branch / clock row with `margin-top: 16px`; both seats re-format at the next local midnight.**
+
+Both seats format `node.time` through `formatMessageClock`: same calendar day → `HH:mm`, earlier this year → `M月D日 HH:mm`, other years → `YYYY年M月D日 HH:mm`. `useCalendarDay` is a component-local day tick (timeout to the next local midnight) so memoized rows re-render when the calendar day changes without a new framework hook. `MessageItem` places the label before copy (figma `388:20051`). `AssistantMarkdown` places it after branch (figma `43:32997`) and only when `streaming` is false with a known event time; the streaming tail omits the row. Copy writes joined text blocks. Branch stays a chrome stub. Hover-capable pointers keep both footers opacity-hidden until hover/focus-within. Clipboard write and the clock helpers live in `message-chrome.ts`. The assembled surface is pinned by `apps/web/tests/message-actions.e2e.ts` (cold-seeded history + aria golden); aria normalization collapses every clock shape to `{{clock}}`.
+
+## Alternatives considered
+
+**Show assistant IconActions during streaming.** Rejected: the request is to reveal the row only after output completes; mid-stream chrome would flicker and invite copying a partial answer.
+
+**Wire branch to a real session fork.** Rejected for this change: same rationale as the archived [user IconActions note](../../archived/feature/2026-07-27-user-message-icon-actions.md) — the mutation path is unspecified; the button reserves the design seat.
+
+**Publish the calendar day through a chat store or inject hook.** Rejected: the day tick is presentation-only local state with no cross-entry consumers; a component-local timeout matches the client rule that behavioral hooks may own state that does not subscribe to an external source.
+
+## Consequences
+
+Settled assistant answers expose copy and the event clock immediately; branch stays a stub. User and assistant clocks share the same day/year widening rules and refresh after midnight without a message mutation. Per-message paging remains a deferred footer seat in the package README. Package tests pin the three clock shapes and the midnight widen; the web e2e scenario pins the assembled IconActions chrome.
--- a/.agents/notes/implemented/feature/2026-07-29-web-message-icon-actions-and-clock.zh.md
+++ b/.agents/notes/implemented/feature/2026-07-29-web-message-icon-actions-and-clock.zh.md
@@ -0,0 +1,27 @@
+# Agent Note: Web 消息 IconActions 与时钟
+
+Status: implemented
+
+[English](2026-07-29-web-message-icon-actions-and-clock.md) | 中文
+
+## 问题
+
+Web 聊天的用户气泡已有复制／分支／编辑 IconActions，但没有时钟。已定稿的 assistant 叙述下方完全没有操作栏，尽管 Harness 设计稿在回答结束后展示复制／分支／时钟。流式回复不得在 token 中途闪出该栏。经 memo 的行在跨午夜时仍保持稳定 props，因此一次性的 `Date.now()` 会让昨日消息一直卡在 `HH:mm`。
+
+## 决策
+
+**用户气泡在既有 IconActions 行前追加感知日期的本地时钟；已定稿的 assistant 节点在正文下追加带 `margin-top: 16px` 的复制／分支／时钟；两边都在下一个本地午夜重新格式化。**
+
+两边都通过 `formatMessageClock` 格式化 `node.time`：同一日历日 → `HH:mm`，同年更早 → `M月D日 HH:mm`，跨年 → `YYYY年M月D日 HH:mm`。`useCalendarDay` 是组件本地的日刻度（定时到下一个本地午夜），因此 memo 行在日历日变化时会重渲染，且不新增框架 hook。`MessageItem` 把标签放在复制之前（figma `388:20051`）。`AssistantMarkdown` 把它放在分支之后（figma `43:32997`），且仅在 `streaming` 为 false 且已知事件时间时渲染；流式尾部省略该行。复制写入拼接后的 text 块。分支仍是 chrome stub。具备 hover 能力的指针在 hover／focus-within 前保持两条 footer 透明。剪贴板写入与时钟辅助函数放在 `message-chrome.ts`。组装面由 `apps/web/tests/message-actions.e2e.ts`（冷 seed 历史 + aria golden）钉住；aria 归一化把每种时钟形态折叠为 `{{clock}}`。
+
+## 曾考虑的方案
+
+**在流式过程中展示 assistant IconActions。** 否决：需求是输出完成后才展示该行；中途 chrome 会闪烁，并诱使复制半截回答。
+
+**把分支接到真实的会话 fork。** 本次否决：与已归档的[用户 IconActions 笔记](../../archived/feature/2026-07-27-user-message-icon-actions.md)同一理由——变更路径尚未规定；按钮只预留设计座位。
+
+**通过 chat store 或 inject hook 发布日历日。** 否决：日刻度只是展示层本地状态，没有跨入口消费者；组件本地 timeout 符合「行为 hook 可拥有不订阅外部源的状态」这一客户端规则。
+
+## 后果
+
+已定稿的 assistant 回答立刻暴露复制与事件时钟；分支仍为 stub。用户与 assistant 时钟共用同一套跨天／跨年加宽规则，并在午夜后无需消息变更即可刷新。逐消息分页仍是包 README 中的暂缓 footer 座位。包级测试钉住三种时钟形态与午夜加宽；Web e2e 场景钉住组装后的 IconActions chrome。
--- a/.agents/notes/implemented/process/2026-07-27-worktree-local-lefthook.i18n.yaml
+++ b/.agents/notes/implemented/process/2026-07-27-worktree-local-lefthook.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write .agents/notes/implemented/process/2026-07-27-worktree-local-lefthook.md
-2026-07-27-worktree-local-lefthook.md: d18f6c1bf8fe240759ad48f67ca6b231000eaf2c
-2026-07-27-worktree-local-lefthook.zh.md: 42a1625a3b2ec7b00942dc46b0c9c64058ecd2fc
+2026-07-27-worktree-local-lefthook.md: 75dfd47087356c34005ec4673e174e451a72c660
+2026-07-27-worktree-local-lefthook.zh.md: bc4902769561c3d33d2101de55e28e70d114f39b
--- a/.agents/notes/implemented/process/2026-07-27-worktree-local-lefthook.md
+++ b/.agents/notes/implemented/process/2026-07-27-worktree-local-lefthook.md
@@ -16,9 +16,9 @@ Hook installation is worktree-scoped. With `CI=true` or `GITHUB_ACTIONS=true`, t

 Before upgrading format 0, the installer refuses direct common-config `extensions.*`; it also refuses direct `core.worktree` or `core.bare=true` and non-empty dormant worktree configs that enabling the extension would activate. The migration removes direct `core.bare=false` because false is Git's default. The common repository config and every existing `config.worktree` must be regular files. These checks disable include expansion because Git's repository-format parser also ignores included targets. A repository-scoped lock serializes migration and hook writes; its process ID, random token, file identity, and exact contents must still match at release. Dead or invalid locks require manual recovery rather than automatic breaking.

-Each hook directory carries a JSON ownership marker containing the absolute path last published to worktree config. After a checkout moves, that marker permits replacement of only the exact stale owned value. Before Lefthook runs, the marker and every existing generated hook must be unaliased regular files. The installer resolves the effective scope, origin, and value of `core.hooksPath`, including active `config.worktree` includes; it refuses command-scoped paths, unowned worktree-scoped paths, and unowned reserved directories. An inherited system, global, or common-repository path requires `DSH_LEFTHOOK_ALLOW_HOOKS_PATH_OVERRIDE=1`, which opts only the current worktree into Lefthook. Inactive `includeIf` targets are not recursively inspected because they do not affect the current configuration. Command-scoped Git configuration is removed from the Lefthook subprocess environment after validation.
+Each hook directory carries a JSON ownership marker containing the absolute path last published to worktree config. After a checkout moves, that marker permits replacement of only the exact stale owned value. Git seeds a new linked worktree's `config.worktree` from the main worktree; when that seed contains the marker-backed reserved hook path of a registered worktree, the installer replaces only the new worktree's config with its own path. Before Lefthook runs, the marker and every existing generated hook must be unaliased regular files. The installer resolves the effective scope, origin, and value of `core.hooksPath`, including active `config.worktree` includes; it refuses command-scoped paths, unowned worktree-scoped paths, and unowned reserved directories. An inherited system, global, or common-repository path requires `DSH_LEFTHOOK_ALLOW_HOOKS_PATH_OVERRIDE=1`, which opts only the current worktree into Lefthook. Inactive `includeIf` targets are not recursively inspected because they do not affect the current configuration. Command-scoped Git configuration is removed from the Lefthook subprocess environment after validation.

-If Lefthook fails after changing `core.hooksPath`, the installer restores the previous worktree value; a rollback failure is reported alongside the installation failure. Existing files in `$GIT_COMMON_DIR/hooks` are never removed or rewritten. Focused installer tests pin isolation, migration refusal, ownership and relocation, concurrent installation, custom paths, and rollback.
+If Lefthook fails after changing `core.hooksPath`, the installer restores the previous worktree value; a rollback failure is reported alongside the installation failure. Existing files in `$GIT_COMMON_DIR/hooks` are never removed or rewritten. Focused installer tests pin isolation, copied new-worktree configuration, migration refusal, ownership and relocation, concurrent installation, custom paths, and rollback.

 ## Alternatives considered

--- a/.agents/notes/implemented/process/2026-07-27-worktree-local-lefthook.zh.md
+++ b/.agents/notes/implemented/process/2026-07-27-worktree-local-lefthook.zh.md
@@ -16,9 +16,9 @@ Lefthook 生成的钩子会优先使用安装时从对应 worktree 记录的绝

 升级格式 0 之前，安装程序会拒绝共用配置中直接设置的 `extensions.*`；它还会拒绝直接设置的 `core.worktree` 或 `core.bare=true`，以及启用扩展后将被激活的非空且尚未生效的 worktree 配置。迁移会移除直接设置的 `core.bare=false`，因为 false 是 Git 的默认值。共用仓库配置和每个已有的 `config.worktree` 都必须是常规文件。这些检查会禁用 include 展开，因为 Git 的仓库格式解析器也会忽略 include 目标。仓库级锁会串行化迁移和钩子写入；释放时，锁的进程 ID、随机令牌、文件身份和完整内容必须仍然匹配。所属进程已结束或内容无效的锁必须手动恢复，不会被自动破坏。

-每个钩子目录都有一个 JSON 所有权标记，其中包含上次写入 worktree 配置的绝对路径。检出目录移动后，该标记只允许替换确切的陈旧自有值。Lefthook 运行前，所有权标记和每个已有的生成钩子都必须是不带别名的常规文件。安装程序会解析 `core.hooksPath` 的生效作用域、来源和值，包括通过当前生效的 `config.worktree` include 加载的值；它会拒绝命令作用域路径、非自有的 worktree 作用域路径以及非自有的保留目录。继承自系统、全局或共用仓库配置的路径必须设置 `DSH_LEFTHOOK_ALLOW_HOOKS_PATH_OVERRIDE=1`，从而只让当前 worktree 显式启用 Lefthook。未生效的 `includeIf` 目标不会被递归检查，因为它们不影响当前配置。完成验证后，Lefthook 子进程的环境会移除命令作用域的 Git 配置。
+每个钩子目录都有一个 JSON 所有权标记，其中包含上次写入 worktree 配置的绝对路径。检出目录移动后，该标记只允许替换确切的陈旧自有值。Git 会以主 worktree 的配置为新链接 worktree 初始化 `config.worktree`；当该初始配置包含某个已注册 worktree 中由所有权标记佐证的保留钩子路径时，安装程序只会在新 worktree 的配置中将其替换为新 worktree 自有的路径。Lefthook 运行前，所有权标记和每个已有的生成钩子都必须是不带别名的常规文件。安装程序会解析 `core.hooksPath` 的生效作用域、来源和值，包括通过当前生效的 `config.worktree` include 加载的值；它会拒绝命令作用域路径、非自有的 worktree 作用域路径以及非自有的保留目录。继承自系统、全局或共用仓库配置的路径必须设置 `DSH_LEFTHOOK_ALLOW_HOOKS_PATH_OVERRIDE=1`，从而只让当前 worktree 显式启用 Lefthook。未生效的 `includeIf` 目标不会被递归检查，因为它们不影响当前配置。完成验证后，Lefthook 子进程的环境会移除命令作用域的 Git 配置。

-若 Lefthook 在更改 `core.hooksPath` 后失败，安装程序会恢复先前的 worktree 值；若回滚失败，会与安装失败一并报告。`$GIT_COMMON_DIR/hooks` 中的现有文件绝不会被移除或改写。聚焦的安装程序测试固定了隔离、迁移拒绝、所有权和检出目录移动、并发安装、自定义路径及回滚行为。
+若 Lefthook 在更改 `core.hooksPath` 后失败，安装程序会恢复先前的 worktree 值；若回滚失败，会与安装失败一并报告。`$GIT_COMMON_DIR/hooks` 中的现有文件绝不会被移除或改写。聚焦的安装程序测试固定了隔离、复制的新 worktree 配置、迁移拒绝、所有权和检出目录移动、并发安装、自定义路径及回滚行为。

 ## 考虑过的替代方案

--- a/.agents/notes/implemented/testing/2026-07-24-web-gui-browser-e2e-lane.i18n.yaml
+++ b/.agents/notes/implemented/testing/2026-07-24-web-gui-browser-e2e-lane.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write .agents/notes/implemented/testing/2026-07-24-web-gui-browser-e2e-lane.md
-2026-07-24-web-gui-browser-e2e-lane.md: d9e0a9660ecd6aeb75e835e68f92c0a268423872
-2026-07-24-web-gui-browser-e2e-lane.zh.md: e8c7d1c4596f20d88bd08423549fb6a9f7b0654b
+2026-07-24-web-gui-browser-e2e-lane.md: ce59dcce270d548c91e3719eee8e9c83aea0c154
+2026-07-24-web-gui-browser-e2e-lane.zh.md: bad3dd15ed7b98cc17340666a6c1094d0de057b1
--- a/.agents/notes/implemented/testing/2026-07-24-web-gui-browser-e2e-lane.md
+++ b/.agents/notes/implemented/testing/2026-07-24-web-gui-browser-e2e-lane.md
@@ -42,7 +42,7 @@ The typecheck plane split is structural: the host scaffold, its support module,

 ### Coverage contract

-The lane covers three behavior families. Live-turn scenarios pin ordinary tool execution, cancellation, non-retryable failure, transient retry, resident questions, and mid-turn steering; synchronization uses durable events, `whenIdle()`, or an explicit replay marker rather than delays. Cold-history scenarios seed through the real persistence API and cover history rendering, sidebar search, trajectory and waterfall views, and tool details without model calls. Browser-lifecycle scenarios cover first-send workspace materialization, reload recovery, layout persistence, theme and locale preferences, and workspace create/rename/view operations. Each family asserts the browser surface and the authoritative host state; a stray model call or under-consumed fixture fails teardown.
+The lane covers three behavior families. Live-turn scenarios pin ordinary tool execution, cancellation, non-retryable failure, transient retry, resident questions, and mid-turn steering; synchronization uses durable events, `whenIdle()`, or an explicit replay marker rather than delays. Cold-history scenarios seed through the real persistence API and cover history rendering, sidebar search, trajectory and waterfall views, and tool details without model calls. Browser-lifecycle scenarios cover first-send workspace materialization, reload recovery, layout reset, theme and locale preferences, and workspace create/rename/view operations. Each family asserts the browser surface and the authoritative host state; a stray model call or under-consumed fixture fails teardown.

 ### CI stance

--- a/.agents/notes/implemented/testing/2026-07-24-web-gui-browser-e2e-lane.zh.md
+++ b/.agents/notes/implemented/testing/2026-07-24-web-gui-browser-e2e-lane.zh.md
@@ -42,7 +42,7 @@ Web GUI 以一条真实组装链交付——chromium 页面 → client 插件 bu

 ### 覆盖契约

-该车道覆盖三类行为。实时轮次场景钉住普通工具执行、取消、不可重试失败、瞬态重试、常驻提问与轮次中途 steering；同步依赖持久事件、`whenIdle()` 或显式回放标记，而不使用延时。冷历史场景通过真实持久化 API 播种，在不调用模型的情况下覆盖历史渲染、侧栏搜索、Trajectory 与 Waterfall 视图及工具详情。浏览器生命周期场景覆盖首次发送时物化工作区、重新加载恢复、布局持久化、主题与语言偏好，以及工作区的创建、重命名和视图操作。每类场景都断言浏览器表面和权威的 host 状态；离群的模型调用或未耗尽的 fixture 会使拆卸失败。
+该车道覆盖三类行为。实时轮次场景钉住普通工具执行、取消、不可重试失败、瞬态重试、常驻提问与轮次中途 steering；同步依赖持久事件、`whenIdle()` 或显式回放标记，而不使用延时。冷历史场景通过真实持久化 API 播种，在不调用模型的情况下覆盖历史渲染、侧栏搜索、Trajectory 与 Waterfall 视图及工具详情。浏览器生命周期场景覆盖首次发送时物化工作区、重新加载恢复、布局重置、主题与语言偏好，以及工作区的创建、重命名和视图操作。每类场景都断言浏览器表面和权威的 host 状态；离群的模型调用或未耗尽的 fixture 会使拆卸失败。

 ### CI 立场

--- a/AGENTS.md
+++ b/AGENTS.md
@@ -113,7 +113,7 @@ Real-API tests and demos read `DEEPSEEK_API_KEY`, optional `DEEPSEEK_BASE_URL`,
 - **Testing policy** — [docs/testing.md](docs/testing.md). Every non-trivial model- or product-user-visible behavior change adds or updates a keyless snapshot through a real runnable example in the same PR; package tests, e2e-only assertions, and mock-only fixtures do not substitute for the assembled application transcript. Fixtures must replay on macOS/Linux; fix fixtures, not normalizers.
 - **A tool's UI render intent is part of its design**, decided up front (`generic`/`terminal`/`diff`, `locations`); presentation methods are pure functions of `args` ([cookbook](docs/cookbook/adding-a-tool.md)).
 - **Plan unit, e2e, and snapshot coverage** for new seams, lifecycle shapes, and transcript surfaces; missing snapshot-harness support is part of the implementation, not deferred follow-up.
- **Use incremental merge commits.** Split independent changes; never squash, rebase, or rewrite pushed history. Fix the introducing PR before merging down-stack. If the base advances mid-merge, never restart: finish the checkpoint, push when authorized, then merge the newer tip separately ([rationale](.agents/notes/implemented/process/2026-07-26-incremental-pr-base-retargeting.md)).
+- **Use incremental merge commits.** Split independent changes. Pushed history may be rewritten before review; afterward prefer new commits. Fix the introducing PR before merging down-stack. If the base advances mid-merge, finish the checkpoint, push when authorized, then merge the newer tip separately ([rationale](.agents/notes/implemented/process/2026-07-26-incremental-pr-base-retargeting.md)).
 - **Label PRs:** one kind (`feature`/`bug-fix`/`doc`/`testing`/`cleanup`), each matching area; the [taxonomy](.agents/notes/implemented/process/2026-07-25-semantic-pr-label-taxonomy.md) is extensible.
 - TODO markers: `FIXME`/`TODO`/`XXX` by urgency ([semantics](docs/development.md)).
 - Files end with exactly one trailing newline; `git diff --cached --check` (pre-commit) gates it.
--- a/apps/web/tests/code-mode-round.e2e.ts
+++ b/apps/web/tests/code-mode-round.e2e.ts
@@ -118,14 +118,14 @@ describe('web e2e: Code Mode round renders nested sub-calls', () => {
    expect(await nest.locator('[data-state="error"]').count()).toBeGreaterThanOrEqual(1)
  }, 60_000)

-  it.skipIf(MODE === 'record')('a bash sub-row click leaves the details panel collapsed', async () => {
+  it.skipIf(MODE === 'record')('a bash sub-row click preserves the details panel state', async () => {
    onTestFailed(() => saveFailureShot(page, 'web-e2e-code-mode-details'))
    const nest = page.locator('[data-subcalls]').first()
    const frame = page.locator('[data-details-collapsed], [class*="frame"]').first()
-    expect(await frame.getAttribute('data-details-collapsed')).not.toBeNull()
+    const before = await frame.getAttribute('data-details-collapsed')
    await nest.locator('[data-sample="bash-global"]').first().click()
-    // Tool rows no longer open details; the column stays width 0.
-    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).not.toBeNull()
+    // Tool rows never change the details column's current open/closed state.
+    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).toBe(before)
  })

  it.skipIf(MODE === 'record')('matches the conversation aria golden with stable anchors', async () => {
--- a/apps/web/tests/details-session-lifecycle.e2e.ts
+++ b/apps/web/tests/details-session-lifecycle.e2e.ts
@@ -0,0 +1,95 @@
+// Keyless browser regression for the details column's Session ownership.
+// The shipped composition retains geometry through unselected states and closes it only when a different Session takes ownership.
+import { readFile } from 'node:fs/promises'
+import { fileURLToPath } from 'node:url'
+import type { Browser, Page } from 'playwright'
+import { chromium } from 'playwright'
+import { afterAll, beforeAll, describe, expect, it, onTestFailed } from 'vitest'
+import {
+  fixtureUserPrompts, launchWebScaffold, seedSession, watchConsole, webSnapshotMode, type WebScaffold,
+} from './scaffold.ts'
+import { connectFreshWorkspace, saveFailureShot } from './support.ts'
+
+const FIXTURE = fileURLToPath(new URL('./snapshots/lifecycle-chrome/session.jsonl', import.meta.url))
+const SEED_FIXTURE = fileURLToPath(new URL('./snapshots/seeded-history/seed.jsonl', import.meta.url))
+const PROMPT = 'Reply with the single word LIGHTHOUSE and stop.'
+const MODE = webSnapshotMode()
+
+/** Last AppFrame grid track in CSS pixels. */
+async function detailsTrack(page: Page): Promise<number> {
+  return await appFrame(page).evaluate((element) => {
+    const tracks = getComputedStyle(element).gridTemplateColumns.split(' ')
+    return Number.parseFloat(tracks.at(-1) ?? 'NaN')
+  })
+}
+
+/** AppFrame is the only product element with an inline grid track template. */
+function appFrame(page: Page) {
+  return page.locator('[style*="grid-template-columns"]').first()
+}
+
+describe.skipIf(MODE === 'record')('web e2e: details panel follows the current Session lifecycle', () => {
+  let scaffold: WebScaffold
+  let browser: Browser
+  let page: Page
+  let tripwire: ReturnType<typeof watchConsole>
+
+  beforeAll(async () => {
+    const fixture = await readFile(FIXTURE, 'utf8')
+    expect(fixtureUserPrompts(fixture)).toEqual([PROMPT])
+    scaffold = await launchWebScaffold({ replayFixture: FIXTURE, paceMs: 5 })
+    await seedSession(scaffold, await readFile(SEED_FIXTURE, 'utf8'), 'details-session-lifecycle-seed')
+    browser = await chromium.launch()
+    page = await browser.newPage({ viewport: { width: 1680, height: 1000 } })
+    tripwire = watchConsole(page)
+    await page.goto(scaffold.baseUrl, { waitUntil: 'load' })
+    await appFrame(page).waitFor({ timeout: 30_000 })
+    await connectFreshWorkspace(page)
+  }, 120_000)
+
+  afterAll(async () => {
+    await browser?.close()
+    await scaffold?.close()
+  })
+
+  it('retains geometry through hero and closes it for a different Session', async () => {
+    onTestFailed(() => saveFailureShot(page, 'web-e2e-details-session-lifecycle'))
+    const settled = scaffold.whenTurnSettled()
+    const input = page.locator('textarea').first()
+    await input.fill(PROMPT)
+    await input.press('Enter')
+    await settled
+    await page.getByText('LIGHTHOUSE', { exact: true }).waitFor({ timeout: 15_000 })
+
+    await expect.poll(() => detailsTrack(page), { timeout: 5_000 }).toBe(360)
+    expect(await page.getByText('详情', { exact: true }).count()).toBe(1)
+
+    await page.getByRole('button', { name: 'New session', exact: true }).last().click()
+    await page.getByText("Let's start building", { exact: false }).waitFor({ timeout: 15_000 })
+    await expect.poll(() => detailsTrack(page), { timeout: 5_000 }).toBe(0)
+    expect(await page.getByText('详情', { exact: true }).isVisible()).toBe(false)
+
+    const original = page.locator('[role=treeitem]').filter({ hasText: 'Reply with the single word' }).first()
+    await original.click()
+    await page.getByText('LIGHTHOUSE', { exact: true }).waitFor({ timeout: 15_000 })
+    await expect.poll(() => detailsTrack(page), { timeout: 5_000 }).toBe(360)
+    expect(await page.getByText('详情', { exact: true }).count()).toBe(1)
+
+    const ungrouped = page.getByText('Ungrouped', { exact: true })
+    const ungroupedRow = ungrouped.locator('..').locator('..')
+    const ungroupedSection = ungroupedRow.locator('..')
+    await expect.poll(async () => {
+      if (await ungroupedRow.getAttribute('aria-expanded') !== 'true') {
+        await ungrouped.click()
+        await page.waitForTimeout(50)
+      }
+      return await ungroupedRow.getAttribute('aria-expanded')
+    }, { timeout: 5_000 }).toBe('true')
+    const seeded = ungroupedSection.locator('[role="treeitem"]').nth(1)
+    await seeded.click()
+    await page.getByText('DONE', { exact: true }).waitFor({ timeout: 15_000 })
+    await expect.poll(() => detailsTrack(page), { timeout: 5_000 }).toBe(0)
+    expect(tripwire.pageErrors).toEqual([])
+    expect(tripwire.warnings).toEqual([])
+  }, 90_000)
+})
--- a/apps/web/tests/lifecycle-chrome.e2e.ts
+++ b/apps/web/tests/lifecycle-chrome.e2e.ts
@@ -101,23 +101,15 @@ describe('web e2e: lifecycle & chrome (workspace flow / reload / dark mode)', ()

  it.skipIf(MODE === 'record')('recovers the whole surface across a reload from the log alone', async () => {
    onTestFailed(() => saveFailureShot(page, 'web-e2e-lifecycle-reload'))
-    // Fold a layout preference into the same reload: collapse the sidebar
-    // (persisted under dsh.layout.panels) before reloading.
-    await page.getByRole('button', { name: 'Collapse sidebar' }).click()
-    await expect.poll(() => page.getByRole('button', { name: 'Open sidebar' }).count(), { timeout: 10_000 }).toBe(1)
    const warningStart = tripwire.warnings.length
    await page.reload({ waitUntil: 'load' })
    await page.waitForSelector('[class*="frame"]', { timeout: 30_000 })
    acknowledgeReloadConnectionLoss(tripwire, warningStart)
-    // Layout persisted: the sidebar comes back collapsed.
-    await expect.poll(() => page.getByRole('button', { name: 'Open sidebar' }).count(), { timeout: 10_000 }).toBe(1)
    // Selection persisted (dsh.sessions.current) and history replayed: the
    // recorded turn re-renders from session.history with zero model calls —
    // the replay cursor was fully consumed before the reload, so any stray
    // request would fail the scenario loudly at close().
    await expect.poll(() => page.getByText('LIGHTHOUSE', { exact: true }).count(), { timeout: 15_000 }).toBeGreaterThanOrEqual(1)
-    // Expand back and confirm the tree still lists the materialized session.
-    await page.getByRole('button', { name: 'Open sidebar' }).click()
    await expect.poll(() => page.locator('[role="treeitem"][aria-selected="true"]').count(), { timeout: 10_000 }).toBe(1)
    // Golden of the recovered conversation region: rebuilt from the log, it
    // must render the same settled transcript the live turn produced.
--- a/apps/web/tests/message-actions.e2e.ts
+++ b/apps/web/tests/message-actions.e2e.ts
@@ -0,0 +1,93 @@
+// Web e2e scenario: message IconActions + clocks. Cold-seeds the seeded-history
+// fixture (zero model calls) and pins the settled conversation aria after the
+// user/assistant footers are focus-revealed — the surface package jsdom tests
+// cannot substitute for (docs/testing.md snapshot rule).
+import { mkdir, readFile, writeFile } from 'node:fs/promises'
+import { join } from 'node:path'
+import { fileURLToPath } from 'node:url'
+import type { Browser, Page } from 'playwright'
+import { chromium } from 'playwright'
+import { afterAll, beforeAll, describe, expect, it, onTestFailed } from 'vitest'
+import {
+  assertFixtureInventory, captureStableAria, compareOrRefreshGolden, fixtureUserPrompts,
+  launchWebScaffold, seedSession, watchConsole, webSnapshotMode, type WebScaffold,
+} from './scaffold.ts'
+import { saveFailureShot } from './support.ts'
+
+const SNAPSHOT_DIR = fileURLToPath(new URL('./snapshots/message-actions', import.meta.url))
+// Borrowed read-only: this scenario needs any settled user+assistant pair, not
+// a new recording (workspace-management / sidebar-scrollbar pattern).
+const SEED = fileURLToPath(new URL('./snapshots/seeded-history/seed.jsonl', import.meta.url))
+const UI_EXPECTED = join(SNAPSHOT_DIR, 'ui.expected.md')
+const MODE = webSnapshotMode()
+const SEED_ID = 'message-actions-web-e2e'
+
+const PROMPT = 'Use the read tool twice in one assistant message: read a.txt and b.txt. Then reply with the single word DONE and stop.'
+
+describe('web e2e: message IconActions and clocks on settled history', () => {
+  let scaffold: WebScaffold
+  let browser: Browser
+  let page: Page
+  let tripwire: ReturnType<typeof watchConsole>
+
+  beforeAll(async () => {
+    scaffold = await launchWebScaffold({})
+    const sessionCwd = join(scaffold.workspaceCwd, 'workspace')
+    await mkdir(sessionCwd, { recursive: true })
+    await writeFile(join(sessionCwd, 'a.txt'), 'alpha\n')
+    await writeFile(join(sessionCwd, 'b.txt'), 'beta\n')
+    const raw = await readFile(SEED, 'utf8')
+    expect(fixtureUserPrompts(raw), 'borrowed seed must carry the drive prompt').toEqual([PROMPT])
+    await seedSession(scaffold, raw, SEED_ID)
+    browser = await chromium.launch()
+    page = await browser.newPage({ viewport: { width: 1680, height: 1000 } })
+    tripwire = watchConsole(page)
+    await page.goto(scaffold.baseUrl, { waitUntil: 'load' })
+    await page.waitForSelector('[class*="frame"]', { timeout: 30_000 })
+  }, 120_000)
+
+  afterAll(async () => {
+    await browser?.close()
+    await scaffold?.close()
+  })
+
+  it.skipIf(MODE === 'record')('lists the seeded session and reveals user/assistant IconActions', async () => {
+    onTestFailed(() => saveFailureShot(page, 'web-e2e-message-actions'))
+    const groupRow = page.locator('[role="treeitem"]').first()
+    await groupRow.waitFor({ timeout: 15_000 })
+    await groupRow.click()
+    const sessionRow = page.locator('[role="treeitem"]').nth(1)
+    await sessionRow.waitFor({ timeout: 10_000 })
+    await sessionRow.click()
+    await expect.poll(() => page.getByText('DONE', { exact: true }).count(), { timeout: 15_000 }).toBe(1)
+
+    // Focus-reveal the footers (hover:hover keeps them opacity-hidden until
+    // hover/focus-within). User has three actions; each finalized assistant
+    // text node has copy + branch.
+    const copyButtons = page.getByRole('button', { name: '复制' })
+    await expect.poll(() => copyButtons.count(), { timeout: 10_000 }).toBeGreaterThanOrEqual(2)
+    await copyButtons.first().focus()
+    await expect.poll(() => page.getByRole('button', { name: '在新对话中分支' }).count(), { timeout: 5_000 })
+      .toBeGreaterThanOrEqual(2)
+    await expect.poll(() => page.getByRole('button', { name: '编辑' }).count(), { timeout: 5_000 }).toBe(1)
+  }, 60_000)
+
+  it.skipIf(MODE === 'record')('matches the conversation aria golden with IconActions and clocks', async () => {
+    onTestFailed(() => saveFailureShot(page, 'web-e2e-message-actions-aria'))
+    await page.getByRole('button', {
+      name: '选择模型，当前 deepseek-v4-flash',
+    }).waitFor({ timeout: 10_000 })
+    // Keep a footer focused so opacity-hidden actions stay in the a11y tree
+    // as an active/focused control during the capture.
+    await page.getByRole('button', { name: '复制' }).first().focus()
+    const snapshot = (await captureStableAria(page, '[class*="centerCol"]', scaffold.workspaceCwd))
+      .split(SEED_ID).join('{{seededId}}')
+    await compareOrRefreshGolden(UI_EXPECTED, snapshot, MODE)
+  })
+
+  it.skipIf(MODE === 'record')('issued zero model calls and kept a closed inventory', async () => {
+    expect(tripwire.pageErrors).toEqual([])
+    expect(tripwire.warnings).toEqual([])
+    await assertFixtureInventory(SNAPSHOT_DIR, ['ui.expected.md'])
+  })
+})
--- a/apps/web/tests/navigation-panes.e2e.ts
+++ b/apps/web/tests/navigation-panes.e2e.ts
@@ -153,20 +153,20 @@ describe('web e2e: navigation & panes over a rich seeded session', () => {
    await compareOrRefreshGolden(WATERFALL_EXPECTED, snapshot, MODE)
  }, 60_000)

-  it.skipIf(MODE === 'record')('bash and file-path rows leave the details column collapsed', async () => {
+  it.skipIf(MODE === 'record')('bash and file-path rows preserve the details column state', async () => {
    onTestFailed(() => saveFailureShot(page, 'web-e2e-navigation-details'))
    await page.getByRole('tab', { name: 'Chat' }).click()
    const bashRow = page.locator('[data-sample="bash-global"]').first()
    await bashRow.waitFor({ timeout: 15_000 })
    const frame = page.locator('[data-details-collapsed], [class*="frame"]').first()
-    expect(await frame.getAttribute('data-details-collapsed')).not.toBeNull()
+    const before = await frame.getAttribute('data-details-collapsed')
    await bashRow.click()
-    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).not.toBeNull()
+    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).toBe(before)
    // Read summaries are host-open file links; they also must not open details.
    const fileLink = page.locator('[data-variant="read"] button').first()
    await fileLink.waitFor({ timeout: 10_000 })
    await fileLink.click()
-    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).not.toBeNull()
+    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).toBe(before)
  }, 60_000)

  it.skipIf(MODE === 'record')('issued zero model calls and stayed clean', async () => {
--- a/apps/web/tests/scaffold.ts
+++ b/apps/web/tests/scaffold.ts
@@ -389,6 +389,11 @@ function normalizeAria(snapshot: string, workspaceCwd: string): string {
    .split(base).join('{{workspace}}')
    .replace(/[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}/gi, '{{uuid}}')
    .replace(/\b\d+(?:\.\d+)?(?:ms|s|秒)\b/g, '{{duration}}')
+    // Message IconActions clocks widen by calendar day/year; collapse every
+    // shape so goldens stay stable across midnight and year boundaries.
+    .replace(/\d{4}年\d{1,2}月\d{1,2}日 \d{2}:\d{2}/g, '{{clock}}')
+    .replace(/\d{1,2}月\d{1,2}日 \d{2}:\d{2}/g, '{{clock}}')
+    .replace(/(?<!\d)\d{2}:\d{2}(?!\d)/g, '{{clock}}')
 }

 /**
--- a/apps/web/tests/seeded-history.e2e.ts
+++ b/apps/web/tests/seeded-history.e2e.ts
@@ -132,7 +132,7 @@ describe('web e2e: seeded history renders through cold resume', () => {
    await compareOrRefreshGolden(UI_EXPECTED, snapshot, MODE)
  })

-  it.skipIf(MODE === 'record')('file-path tool rows rebuilt from the cold log stay details-inert', async () => {
+  it.skipIf(MODE === 'record')('file-path tool rows rebuilt from the cold log preserve details state', async () => {
    onTestFailed(() => saveFailureShot(page, 'web-e2e-seeded-toolrow'))
    // Interaction over cold-resumed history: read summaries are host-open
    // file links (not expand-in-place / not details). Runs after the golden
@@ -140,9 +140,9 @@ describe('web e2e: seeded history renders through cold resume', () => {
    const fileLink = page.locator('[data-variant="read"] button').first()
    await fileLink.waitFor({ timeout: 10_000 })
    const frame = page.locator('[data-details-collapsed], [class*="frame"]').first()
-    expect(await frame.getAttribute('data-details-collapsed')).not.toBeNull()
+    const before = await frame.getAttribute('data-details-collapsed')
    await fileLink.click()
-    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).not.toBeNull()
+    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).toBe(before)
    // Path label survives from the recorded args (a.txt).
    await expect.poll(() => page.getByText('a.txt', { exact: false }).count(), { timeout: 5_000 }).toBeGreaterThan(0)
  })
--- a/apps/web/tests/smoke-real.e2e.ts
+++ b/apps/web/tests/smoke-real.e2e.ts
@@ -469,7 +469,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY || notReady.length > 0)('web smoke
    await screen(page, '09-details-closed')
  }, 150_000)

-  it('6 sidebar drag widens the column and persists across reload', async () => {
+  it('6 sidebar drag widens the column and resets across reload', async () => {
    onTestFailed(() => saveFailureShot(page, 'w5-drag'))
    const before = await firstTrack(page)
    const handle = page.locator('[class*="handle"]').first()
@@ -484,7 +484,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY || notReady.length > 0)('web smoke
    await screen(page, '10-sidebar-dragged')
    await page.reload({ waitUntil: 'load' })
    await page.waitForSelector('[class*="frame"]', { timeout: 30_000 })
-    expect(await firstTrack(page)).toBe(after)
+    expect(await firstTrack(page)).toBe(before)
  })

  it('7 dark mode: the body attribute cascades the token sheets', async () => {
--- a/apps/web/tests/snapshots/code-mode-round/ui.expected.md
+++ b/apps/web/tests/snapshots/code-mode-round/ui.expected.md
@@ -5,7 +5,7 @@
    - tab "Chat" [selected]
    - tab "Trajectory"
    - tab "Waterfall"
- text: "Using ONE run_code program: run bash `echo CODE_ROUND_OK`, then read the file missing.txt catching its error in the program. Return an object with both outcomes. Then reply DONE and stop."
+- text: "Using ONE run_code program: run bash `echo CODE_ROUND_OK`, then read the file missing.txt catching its error in the program. Return an object with both outcomes. Then reply DONE and stop. {{clock}}"
 - button "复制":
  - img
 - button "在新对话中分支":
@@ -17,6 +17,11 @@
  - img
  - img
  - text: "Think The user wants me to write a single `run_code` program that:"
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}}
 - button:
  - img
  - img
@@ -29,7 +34,11 @@
  - img
  - text: Think The program ran successfully. Let me now reply DONE as instructed.
 - paragraph: DONE
- text: 8.3k uncached input · 252 output · 9k cache read · cache hit 52% · context 7% of 128k · 1 turns · 2 steps
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}} 8.3k uncached input · 252 output · 9k cache read · cache hit 52% · context 7% of 128k · 1 turns · 2 steps
 - textbox "Message the agent"
 - button "Add attachment":
  - img
--- a/apps/web/tests/snapshots/cordis-tool-round/ui.expected.md
+++ b/apps/web/tests/snapshots/cordis-tool-round/ui.expected.md
@@ -5,7 +5,7 @@
    - tab "Chat" [selected]
    - tab "Trajectory"
    - tab "Waterfall"
- text: "Use only Cordis tools. First call cordis_inspect with what \"temporary\". Then call cordis_mount with this exact code: \"return { name: \\\"snapshot-noop\\\", apply(ctx) {} }\". Read its returned id and call cordis_unmount with that exact id. After all three calls succeed, reply exactly CORDIS_UI_DONE and stop."
+- text: "Use only Cordis tools. First call cordis_inspect with what \"temporary\". Then call cordis_mount with this exact code: \"return { name: \\\"snapshot-noop\\\", apply(ctx) {} }\". Read its returned id and call cordis_unmount with that exact id. After all three calls succeed, reply exactly CORDIS_UI_DONE and stop. {{clock}}"
 - button "复制":
  - img
 - button "在新对话中分支":
@@ -17,6 +17,11 @@
  - img
  - img
  - text: "Think The user wants me to:"
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}}
 - button:
  - img
  - img
@@ -25,6 +30,11 @@
  - img
  - img
  - text: "Think Good, no temporary plugins running. Now step 2: call cordis_mount with the exact code."
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}}
 - button [expanded]:
  - img
 - text: Mount temporary Plugin typescript
@@ -34,6 +44,11 @@
  - img
  - img
  - text: "Think The id is \"dyn-1\". Now step 3: call cordis_unmount with that id."
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}}
 - button:
  - img
  - img
@@ -43,7 +58,11 @@
  - img
  - text: Think All three calls succeeded. I should now reply exactly "CORDIS_UI_DONE" and stop.
 - paragraph: CORDIS_UI_DONE
- text: 15.3k uncached input · 312 output · 51.2k cache read · cache hit 77% · context 13% of 128k · 1 turns · 4 steps
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}} 15.3k uncached input · 312 output · 51.2k cache read · cache hit 77% · context 13% of 128k · 1 turns · 4 steps
 - textbox "Message the agent"
 - button "Add attachment":
  - img
--- a/apps/web/tests/snapshots/fresh-round-trip/ui.expected.md
+++ b/apps/web/tests/snapshots/fresh-round-trip/ui.expected.md
@@ -5,7 +5,7 @@
    - tab "Chat" [selected]
    - tab "Trajectory"
    - tab "Waterfall"
- text: "Use the bash tool to run exactly: echo WEB_E2E_OK. Then reply with the single word DONE and stop."
+- text: "Use the bash tool to run exactly: echo WEB_E2E_OK. Then reply with the single word DONE and stop. {{clock}}"
 - button "复制":
  - img
 - button "在新对话中分支":
@@ -17,6 +17,11 @@
  - img
  - img
  - text: Think The user wants me to run a simple bash command and reply with "DONE".
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}}
 - img
 - text: Bash Echo the test string
 - button "Think The command executed successfully and output \"WEB_E2E_OK\". I just need to reply with \"DONE\".":
@@ -24,7 +29,11 @@
  - img
  - text: Think The command executed successfully and output "WEB_E2E_OK". I just need to reply with "DONE".
 - paragraph: DONE
- text: 219 uncached input · 111 output · 15.5k cache read · cache hit 99% · context 6% of 128k · 1 turns · 2 steps
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}} 219 uncached input · 111 output · 15.5k cache read · cache hit 99% · context 6% of 128k · 1 turns · 2 steps
 - textbox "Message the agent"
 - button "Add attachment":
  - img
--- a/apps/web/tests/snapshots/lifecycle-chrome/reloaded.expected.md
+++ b/apps/web/tests/snapshots/lifecycle-chrome/reloaded.expected.md
@@ -5,7 +5,7 @@
    - tab "Chat" [selected]
    - tab "Trajectory"
    - tab "Waterfall"
- text: Reply with the single word LIGHTHOUSE and stop.
+- text: Reply with the single word LIGHTHOUSE and stop. {{clock}}
 - button "复制":
  - img
 - button "在新对话中分支":
@@ -18,7 +18,11 @@
  - img
  - text: Think The user wants me to reply with a single word. Let me comply.
 - paragraph: LIGHTHOUSE
- text: 109 uncached input · 21 output · 7.7k cache read · cache hit 99% · context unknown · 1 turns · 1 steps
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}} 109 uncached input · 21 output · 7.7k cache read · cache hit 99% · context unknown · 1 turns · 1 steps
 - textbox "Message the agent"
 - button "Add attachment":
  - img
--- a/apps/web/tests/snapshots/live-interactions/cancel.expected.md
+++ b/apps/web/tests/snapshots/live-interactions/cancel.expected.md
@@ -5,7 +5,7 @@
    - tab "Chat" [selected]
    - tab "Trajectory"
    - tab "Waterfall"
- text: Reply with a one-sentence description of event sourcing, then stop.
+- text: Reply with a one-sentence description of event sourcing, then stop. {{clock}}
 - button "复制":
  - img
 - button "在新对话中分支":
@@ -14,7 +14,12 @@
  - img
 - button "▸ 上下文注入"
 - paragraph: partial
- text: 已停止 0 uncached input · 0 output · 0 cache read · context 4% of 128k · 1 turns · 1 steps
+- text: 已停止
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}} 0 uncached input · 0 output · 0 cache read · context 4% of 128k · 1 turns · 1 steps
 - textbox "Message the agent"
 - button "Add attachment":
  - img
--- a/apps/web/tests/snapshots/live-interactions/error-auth.expected.md
+++ b/apps/web/tests/snapshots/live-interactions/error-auth.expected.md
@@ -5,7 +5,7 @@
    - tab "Chat" [selected]
    - tab "Trajectory"
    - tab "Waterfall"
- text: Reply with a one-sentence description of event sourcing, then stop.
+- text: Reply with a one-sentence description of event sourcing, then stop. {{clock}}
 - button "复制":
  - img
 - button "在新对话中分支":
--- a/apps/web/tests/snapshots/live-interactions/retry.expected.md
+++ b/apps/web/tests/snapshots/live-interactions/retry.expected.md
@@ -5,7 +5,7 @@
    - tab "Chat" [selected]
    - tab "Trajectory"
    - tab "Waterfall"
- text: Reply with a one-sentence description of event sourcing, then stop.
+- text: Reply with a one-sentence description of event sourcing, then stop. {{clock}}
 - button "复制":
  - img
 - button "在新对话中分支":
@@ -18,7 +18,11 @@
  - img
  - text: Think The user is asking for a one-sentence description of event sourcing. This is a straightforward knowledge question that doesn't require any skill loading or tool calls.
 - paragraph: Event sourcing is a pattern where all changes to an application's state are stored as an immutable, append-only sequence of events, rather than persisting only the current state, enabling full auditability, temporal queries, and event-driven architectures.
- text: 110 uncached input · 79 output · 7.7k cache read · cache hit 99% · context 4% of 128k · 1 turns · 1 steps
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}} 110 uncached input · 79 output · 7.7k cache read · cache hit 99% · context 4% of 128k · 1 turns · 1 steps
 - textbox "Message the agent"
 - button "Add attachment":
  - img
--- a/apps/web/tests/snapshots/message-actions/ui.expected.md
+++ b/apps/web/tests/snapshots/message-actions/ui.expected.md
@@ -0,0 +1,52 @@
+- banner:
+  - navigation "Session hierarchy":
+    - button "Use the read tool twice" [disabled]
+  - tablist:
+    - tab "Chat" [selected]
+    - tab "Trajectory"
+    - tab "Waterfall"
+- text: "Use the read tool twice in one assistant message: read a.txt and b.txt. Then reply with the single word DONE and stop. {{clock}}"
+- button "复制":
+  - img
+- tooltip "复制"
+- button "在新对话中分支":
+  - img
+- button "编辑":
+  - img
+- button "Think The user wants me to read a.txt and b.txt, then reply with \"DONE\". Let me do both reads in parallel.":
+  - img
+  - img
+  - text: Think The user wants me to read a.txt and b.txt, then reply with "DONE". Let me do both reads in parallel.
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}}
+- img
+- text: Read
+- button "a.txt"
+- img
+- text: Read
+- button "b.txt"
+- button "Think Both files have been read. a.txt contains \"alpha\" and b.txt contains \"beta\". I'll now reply with DONE as instructed.":
+  - img
+  - img
+  - text: Think Both files have been read. a.txt contains "alpha" and b.txt contains "beta". I'll now reply with DONE as instructed.
+- paragraph: DONE
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}} 339 uncached input · 135 output · 15.5k cache read · cache hit 98% · context unknown · 1 turns · 2 steps
+- textbox "Message the agent"
+- button "Add attachment":
+  - img
+- text: Danger Full Access
+- combobox "Access mode":
+  - option "Read Only"
+  - option "Workspace Write"
+  - option "Danger Full Access" [selected]
+- button "选择模型，当前 deepseek-v4-flash":
+  - text: deepseek-v4-flash
+  - img
+- button "Send message" [disabled]
--- a/apps/web/tests/snapshots/question-composer/answered.expected.md
+++ b/apps/web/tests/snapshots/question-composer/answered.expected.md
@@ -5,7 +5,7 @@
    - tab "Chat" [selected]
    - tab "Trajectory"
    - tab "Waterfall"
- text: "Use the ask_user_question tool to ask me exactly one question with id \"color\", question \"Which color do you prefer?\", header \"Pick one\", and two options: label \"Blue\" with description \"A cool recessive hue that reads as calm and trustworthy in long reading sessions and dense dashboards.\", and label \"Green\" with description \"A restful mid-spectrum hue with the highest perceived brightness, easiest on the eye over long sessions.\" After I answer, reply with the single word DONE and stop."
+- text: "Use the ask_user_question tool to ask me exactly one question with id \"color\", question \"Which color do you prefer?\", header \"Pick one\", and two options: label \"Blue\" with description \"A cool recessive hue that reads as calm and trustworthy in long reading sessions and dense dashboards.\", and label \"Green\" with description \"A restful mid-spectrum hue with the highest perceived brightness, easiest on the eye over long sessions.\" After I answer, reply with the single word DONE and stop. {{clock}}"
 - button "复制":
  - img
 - button "在新对话中分支":
@@ -17,6 +17,11 @@
  - img
  - img
  - text: Think The user wants me to use the ask_user_question tool with specific parameters. Let me do exactly that.
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}}
 - button:
  - img
  - img
@@ -26,7 +31,11 @@
  - img
  - text: Think The user answered "Blue". I should now reply with the single word DONE and stop.
 - paragraph: DONE
- text: 397 uncached input · 180 output · 8.2k cache read · cache hit 95% · context 4% of 128k · 1 turns · 2 steps
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}} 397 uncached input · 180 output · 8.2k cache read · cache hit 95% · context 4% of 128k · 1 turns · 2 steps
 - textbox "Message the agent"
 - button "Add attachment":
  - img
--- a/apps/web/tests/snapshots/seeded-history/ui.expected.md
+++ b/apps/web/tests/snapshots/seeded-history/ui.expected.md
@@ -5,7 +5,7 @@
    - tab "Chat" [selected]
    - tab "Trajectory"
    - tab "Waterfall"
- text: "Use the read tool twice in one assistant message: read a.txt and b.txt. Then reply with the single word DONE and stop."
+- text: "Use the read tool twice in one assistant message: read a.txt and b.txt. Then reply with the single word DONE and stop. {{clock}}"
 - button "复制":
  - img
 - button "在新对话中分支":
@@ -16,6 +16,11 @@
  - img
  - img
  - text: Think The user wants me to read a.txt and b.txt, then reply with "DONE". Let me do both reads in parallel.
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}}
 - img
 - text: Read
 - button "a.txt"
@@ -27,7 +32,11 @@
  - img
  - text: Think Both files have been read. a.txt contains "alpha" and b.txt contains "beta". I'll now reply with DONE as instructed.
 - paragraph: DONE
- text: 339 uncached input · 135 output · 15.5k cache read · cache hit 98% · context unknown · 1 turns · 2 steps
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}} 339 uncached input · 135 output · 15.5k cache read · cache hit 98% · context unknown · 1 turns · 2 steps
 - textbox "Message the agent"
 - button "Add attachment":
  - img
--- a/apps/web/tests/snapshots/steering/mid-steer.expected.md
+++ b/apps/web/tests/snapshots/steering/mid-steer.expected.md
@@ -5,7 +5,7 @@
    - tab "Chat" [selected]
    - tab "Trajectory"
    - tab "Waterfall"
- text: Use the ask_user_question tool to ask me exactly one question with id "checkpoint", question "Ready to continue?", header "Checkpoint", and options labeled "Yes" and "No". After I answer, reply with one short sentence acknowledging my answer and stop.
+- text: Use the ask_user_question tool to ask me exactly one question with id "checkpoint", question "Ready to continue?", header "Checkpoint", and options labeled "Yes" and "No". After I answer, reply with one short sentence acknowledging my answer and stop. {{clock}}
 - button "复制":
  - img
 - button "在新对话中分支":
@@ -17,6 +17,11 @@
  - img
  - img
  - text: Think The user wants me to use the ask_user_question tool to ask them a specific question with the given parameters. Let me do exactly that.
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}}
 - button:
  - img
  - img
--- a/apps/web/tests/snapshots/steering/settled.expected.md
+++ b/apps/web/tests/snapshots/steering/settled.expected.md
@@ -5,7 +5,7 @@
    - tab "Chat" [selected]
    - tab "Trajectory"
    - tab "Waterfall"
- text: Use the ask_user_question tool to ask me exactly one question with id "checkpoint", question "Ready to continue?", header "Checkpoint", and options labeled "Yes" and "No". After I answer, reply with one short sentence acknowledging my answer and stop.
+- text: Use the ask_user_question tool to ask me exactly one question with id "checkpoint", question "Ready to continue?", header "Checkpoint", and options labeled "Yes" and "No". After I answer, reply with one short sentence acknowledging my answer and stop. {{clock}}
 - button "复制":
  - img
 - button "在新对话中分支":
@@ -17,6 +17,11 @@
  - img
  - img
  - text: Think The user wants me to use the ask_user_question tool to ask them a specific question with the given parameters. Let me do exactly that.
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}}
 - button:
  - img
  - img
@@ -26,7 +31,11 @@
  - img
  - text: Think The user selected "Yes" and wants me to include the word "BANANA" in my final reply. Let me acknowledge their answer.
 - paragraph: Great, let's move forward. BANANA!
- text: 323 uncached input · 156 output · 15.5k cache read · cache hit 98% · context 6% of 128k · 1 turns · 2 steps
+- button "复制":
+  - img
+- button "在新对话中分支":
+  - img
+- text: {{clock}} 323 uncached input · 156 output · 15.5k cache read · cache hit 98% · context 6% of 128k · 1 turns · 2 steps
 - textbox "Message the agent"
 - button "Add attachment":
  - img
--- a/apps/web/tsconfig.json
+++ b/apps/web/tsconfig.json
@@ -28,13 +28,15 @@
    "tests/steering.e2e.ts",
    "tests/navigation-panes.e2e.ts",
    "tests/lifecycle-chrome.e2e.ts",
+    "tests/details-session-lifecycle.e2e.ts",
    "tests/settings-chrome.e2e.ts",
    "tests/workspace-management.e2e.ts",
    "tests/replay-round-trip.e2e.ts",
    "tests/seeded-history.e2e.ts",
    "tests/sidebar-scrollbar.e2e.ts",
    "tests/code-mode-round.e2e.ts",
-    "tests/cordis-tool-round.e2e.ts"
+    "tests/cordis-tool-round.e2e.ts",
+    "tests/message-actions.e2e.ts"
  ],
  "references": [
    {
--- a/docs/development.i18n.yaml
+++ b/docs/development.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write docs/development.md
-development.md: 32339fa2af8c1b6005d9e0b8165d57966a4145ca
-development.zh.md: c74a81346639c6f95568cbd86b401d134d5eb7fc
+development.md: 0a18e29d3da4f694707521e230017e6b22cad740
+development.zh.md: 885b51c701267215cc50d31ecd1694ae2c9af9ca
--- a/docs/development.md
+++ b/docs/development.md
@@ -27,7 +27,7 @@ If hooks are missing because dependencies were restored from cache or `postinsta
 node scripts/install-lefthook.mjs
 ```

-The wrapper refuses user-owned `core.hooksPath` values. An inherited system, global, or common-repository path requires `DSH_LEFTHOOK_ALLOW_HOOKS_PATH_OVERRIDE=1`; command-scoped and worktree-scoped custom paths must be integrated or removed explicitly.
+The wrapper refuses user-owned `core.hooksPath` values. An inherited system, global, or common-repository path requires `DSH_LEFTHOOK_ALLOW_HOOKS_PATH_OVERRIDE=1`. When Git seeds a new worktree with another registered worktree's marker-backed hook path, the wrapper replaces that copied value with the new worktree's own path; command-scoped and other worktree-scoped paths must be integrated or removed explicitly.

 Before enabling worktree config, migrate direct `extensions.*` in a format-0 common config, direct `core.worktree` or `core.bare=true`, and any non-empty dormant `config.worktree`. The common config and every worktree config must be regular files, while the owned hook directory may contain only unaliased regular files.

--- a/docs/development.zh.md
+++ b/docs/development.zh.md
@@ -27,7 +27,7 @@ pnpm install
 node scripts/install-lefthook.mjs
 ```

-包装层会拒绝用户自有的 `core.hooksPath` 值。继承自系统、全局或共用仓库配置的路径必须设置 `DSH_LEFTHOOK_ALLOW_HOOKS_PATH_OVERRIDE=1`；命令作用域和 worktree 作用域的自定义路径必须显式集成或移除。
+包装层会拒绝用户自有的 `core.hooksPath` 值。继承自系统、全局或共用仓库配置的路径必须设置 `DSH_LEFTHOOK_ALLOW_HOOKS_PATH_OVERRIDE=1`。当 Git 使用另一个已注册 worktree 中由所有权标记佐证的钩子路径初始化新 worktree 时，包装层会将这个复制值替换为新 worktree 自有的路径；命令作用域和其他 worktree 作用域的路径必须显式集成或移除。

 启用 worktree 配置之前，请迁移格式 0 共用配置中直接设置的 `extensions.*`，并迁移直接设置的 `core.worktree` 或 `core.bare=true`，以及任何非空且尚未生效的 `config.worktree`。共用配置和每个 worktree 配置都必须是常规文件，而自有钩子目录只能包含不带别名的常规文件。

--- a/packages/client/ui-conversation/README.i18n.yaml
+++ b/packages/client/ui-conversation/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/client/ui-conversation/README.md
-README.md: c60a38ec26d4bca15ce23e51dbaedf3ef36022e4
-README.zh.md: 65c5554a78960fc4f86a6a370772c95429c648c4
+README.md: 4db28ced96abee8d2110abbd09a1c8761aac5d1d
+README.zh.md: 99822a88835103c471ca0364cd57cd13ea8a6434
--- a/packages/client/ui-conversation/README.md
+++ b/packages/client/ui-conversation/README.md
@@ -36,7 +36,7 @@ None; this package neither assembles nor sends a provider request.

 - **The stats line has no duration segment** — assistant `usage` carries token accounting only; elapsed-time needs a host data source.
 - **Details panel is the minimal form** — selected call args/result raw display; the Input/Output/Metadata switch, Prev/Next stepping, and See-in-trajectory deep link are deferred.
- **Assistant footer extensions (IconActions row, per-message paging) are reserved slots** — drawn in the design, not implemented.
+- **Assistant per-message paging is a reserved slot** — drawn in the design, not implemented. The finalized IconActions row (copy / branch / clock) ships; branch remains a chrome stub.
 - **The sparkle icon for the others tool row is a hand-drawn approximation** — the design glyph's vector geometry is not exportable locally; promotion into ui-primitives waits on an exact export.
 - **The approval panel's "Always allow this type" is deferred** — durable grants need a grant-storage design; only allow-once/reject answer today.
 - **TodoPanel truncates long item text to one ellipsized line** — the figma strip has no wrap or expand affordance; full text is not readable inline.
--- a/packages/client/ui-conversation/README.zh.md
+++ b/packages/client/ui-conversation/README.zh.md
@@ -36,7 +36,7 @@ todo 两个面就是在该形状上的两个注册项，都是普通注册方插

 - **统计行没有耗时区段**：assistant `usage` 只携带 token 计数；耗时需要主机数据源。
 - **详情面板是最小形态**：以原始形式显示已选择调用的参数／结果；Input/Output/Metadata 切换、Prev/Next 步进与 See-in-trajectory 深链接暂缓实现。
- **assistant footer 扩展（IconActions 行、逐消息分页）是预留 slot**：设计中已有图稿，尚未实现。
+- **assistant 逐消息分页是预留 slot**：设计中已有图稿，尚未实现。已定稿的 IconActions 行（复制／分支／时钟）已落地；分支仍是 chrome stub。
 - **others 工具行的闪光图标是手绘近似版本**：无法在本地导出设计字形的矢量几何；等到存在精确导出后再将其提升到 ui-primitives。
 - **审批面板的「始终允许此类」暂缓**：持久授权需要授权存储设计；今天只能回答允许一次／拒绝。
 - **TodoPanel 将过长条目截成单行省略号**：figma 条没有换行或展开入口，完整文本无法在行内读完。
--- a/packages/client/ui-conversation/src/client/chat/AssistantMarkdown.module.css
+++ b/packages/client/ui-conversation/src/client/chat/AssistantMarkdown.module.css
@@ -1,14 +1,22 @@
-/* Assistant flow body: full-width narration (figma 16/28), block gap 16. */
+/* Assistant flow body: full-width narration (figma 16/28), block gap 16.
+   IconActions sit below the body with an explicit 16px top margin (figma
+   43:32997) — separate from the body's internal gap so the footer spacing
+   stays fixed when the body is a single block. */

 .root {
  display: flex;
  flex-direction: column;
-  gap: 16px;
  font-size: 16px;
  line-height: 28px;
  color: var(--dsw-alias-label-primary);
 }

+.body {
+  display: flex;
+  flex-direction: column;
+  gap: 16px;
+}
+
 /* Interrupted-turn terminal marker: quiet inline tag, no animation. */
 .stopped {
  align-self: flex-start;
@@ -19,3 +27,18 @@
  font-size: 11px;
  line-height: 18px;
 }
+
+/* Finalized footer offset (figma 43:32997); chrome lives in MessageIconActions. */
+.actions {
+  margin-top: 16px;
+  /* Optical align with 28px icon hit targets that pad 6px past the glyph. */
+  margin-left: -6px;
+}
+
+/* Hover-capable pointers: reveal shared actions on root hover/focus. */
+@media (hover: hover) {
+  .root:hover .actions,
+  .root:focus-within .actions {
+    opacity: 1;
+  }
+}
--- a/packages/client/ui-conversation/src/client/chat/AssistantMarkdown.tsx
+++ b/packages/client/ui-conversation/src/client/chat/AssistantMarkdown.tsx
@@ -4,10 +4,14 @@
 // view groups them into tool rows through its keyed toolview slot (figma
 // step-summary flow). Shared by finalized nodes and the streaming partial;
 // the turn-level loading dots live in the chat view's tail, not here.
+// Finalized nodes append IconActions (copy / branch / clock) once streaming ends.

 import { memo } from 'react'
 import type { AssistantBlock } from '@deepseek-ai/dsh-client-runtime/client'
-import { IconThinkOutline14, JsonBlock, MarkdownText } from '@deepseek-ai/dsh-client-ui-primitives'
+import {
+  IconThinkOutline14, JsonBlock, MarkdownText,
+} from '@deepseek-ai/dsh-client-ui-primitives'
+import { MessageIconActions } from './MessageIconActions.tsx'
 import { ToolRow } from './ToolRow.tsx'
 import css from './AssistantMarkdown.module.css'

@@ -16,6 +20,8 @@ export interface AssistantMarkdownProps {
  streaming: boolean
  /** Frozen partial of an aborted turn: rendered with a 已停止 marker. */
  interrupted?: boolean | undefined
+  /** Unix epoch ms for the finalized IconActions clock; omitted while streaming. */
+  time?: number | undefined
 }

 function firstLine(text: string): string {
@@ -23,6 +29,15 @@ function firstLine(text: string): string {
  return nl === -1 ? text : text.slice(0, nl)
 }

+/** Joined text blocks for the copy action (reasoning / tool heads stay out). */
+function copyText(blocks: readonly AssistantBlock[]): string {
+  const parts: string[] = []
+  for (const block of blocks) {
+    if (block.kind === 'text') parts.push(block.text)
+  }
+  return parts.join('')
+}
+
 /** Reasoning block as the Think variant summary row (figma 39:28304). */
 function ThinkRow({ text, running }: { text: string; running: boolean }) {
  return (
@@ -38,7 +53,9 @@ function ThinkRow({ text, running }: { text: string; running: boolean }) {
  )
 }

-export const AssistantMarkdown = memo(function AssistantMarkdown({ blocks, streaming, interrupted }: AssistantMarkdownProps) {
+export const AssistantMarkdown = memo(function AssistantMarkdown({
+  blocks, streaming, interrupted, time,
+}: AssistantMarkdownProps) {
  const last = blocks.length - 1
  // Tool-call heads render as tool rows in the chat view's grouping pass, so
  // a node that is only those heads (or empty) would paint an empty root
@@ -47,18 +64,30 @@ export const AssistantMarkdown = memo(function AssistantMarkdown({ blocks, strea
    || interrupted === true
    || blocks.some(block => block.kind !== 'tool-call')
  if (!hasVisible) return null
+  // Footer only after the turn settles with a known event time; streaming omits it.
+  const showActions = !streaming && time !== undefined
  return (
    <div className={css.root} data-streaming={streaming || undefined}>
-      {blocks.map((block, i) => {
-        switch (block.kind) {
-          case 'text': return <MarkdownText key={i} text={block.text} streaming={streaming} />
-          case 'reasoning': return <ThinkRow key={i} text={block.text} running={streaming && i === last} />
-          // Grouped into tool rows by ChatView; hasVisible above skips an empty shell.
-          case 'tool-call': return null
-          default: return <JsonBlock key={i} label="未知内容块" payload={block.block} />
-        }
-      })}
-      {interrupted && <span className={css.stopped}>已停止</span>}
+      <div className={css.body}>
+        {blocks.map((block, i) => {
+          switch (block.kind) {
+            case 'text': return <MarkdownText key={i} text={block.text} streaming={streaming} />
+            case 'reasoning': return <ThinkRow key={i} text={block.text} running={streaming && i === last} />
+            // Grouped into tool rows by ChatView; hasVisible above skips an empty shell.
+            case 'tool-call': return null
+            default: return <JsonBlock key={i} label="未知内容块" payload={block.block} />
+          }
+        })}
+        {interrupted && <span className={css.stopped}>已停止</span>}
+      </div>
+      {showActions && (
+        <MessageIconActions
+          text={copyText(blocks)}
+          time={time}
+          clock="end"
+          className={css.actions}
+        />
+      )}
    </div>
  )
 })
--- a/packages/client/ui-conversation/src/client/chat/ChatView.tsx
+++ b/packages/client/ui-conversation/src/client/chat/ChatView.tsx
@@ -332,7 +332,15 @@ export function ChatView({
    }
    const node: ConversationNode = item.node
    if (node.kind === 'assistant') {
-      return <AssistantMarkdown key={item.key} blocks={node.blocks} streaming={false} interrupted={node.interrupted} />
+      return (
+        <AssistantMarkdown
+          key={item.key}
+          blocks={node.blocks}
+          streaming={false}
+          interrupted={node.interrupted}
+          time={node.time}
+        />
+      )
    }
    if (node.kind === 'command') {
      return <CommandRow key={item.key} renderSlot={renderSlot} node={node} />
--- a/packages/client/ui-conversation/src/client/chat/MessageIconActions.module.css
+++ b/packages/client/ui-conversation/src/client/chat/MessageIconActions.module.css
@@ -0,0 +1,53 @@
+/* Shared message IconActions row (user + assistant). Parent modules own
+   hover-reveal selectors and layout offsets via the composed className. */
+
+.actions {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  height: 28px;
+}
+
+/* Clock before icons (user figma 388:20051) / after (assistant 43:32997). */
+.timeStart {
+  padding-right: 12px;
+  font-size: 14px;
+  line-height: 24px;
+  color: var(--dsw-alias-label-tertiary);
+  white-space: nowrap;
+}
+
+.timeEnd {
+  padding-left: 12px;
+  font-size: 14px;
+  line-height: 24px;
+  color: var(--dsw-alias-label-tertiary);
+  white-space: nowrap;
+}
+
+/* Hover-capable pointers: hide until a parent hover/focus rule reveals. */
+@media (hover: hover) {
+  .actions {
+    opacity: 0;
+    transition: opacity var(--ds-transition-duration) var(--ds-ease-in-out);
+  }
+}
+
+.action {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 28px;
+  height: 28px;
+  padding: 6px;
+  border: none;
+  border-radius: 28px;
+  background: transparent;
+  color: var(--dsw-alias-label-tertiary);
+  cursor: pointer;
+}
+
+.action:hover {
+  background: var(--dsw-alias-interactive-bg-hover);
+  color: var(--dsw-alias-label-secondary);
+}
--- a/packages/client/ui-conversation/src/client/chat/MessageIconActions.tsx
+++ b/packages/client/ui-conversation/src/client/chat/MessageIconActions.tsx
@@ -0,0 +1,65 @@
+// Shared IconActions chrome for user and assistant messages: copy / branch
+// live (branch still a stub), date-aware clock, optional edit stub.
+
+import { useCallback } from 'react'
+import {
+  IconBranchOutline16, IconCopyOutline16, IconEditOutline16, Tooltip,
+} from '@deepseek-ai/dsh-client-ui-primitives'
+import { formatMessageClock, writeClipboard } from './message-chrome.ts'
+import { useCalendarDay } from './use-calendar-day.ts'
+import css from './MessageIconActions.module.css'
+
+export interface MessageIconActionsProps {
+  /** Plain text the copy action writes. */
+  text: string
+  /** Unix epoch ms for the clock label. */
+  time: number
+  /** Clock before icons (user) or after (assistant). */
+  clock: 'start' | 'end'
+  /** When true, append the stub edit control (user bubble). */
+  edit?: boolean | undefined
+  /** Parent layout / hover-reveal class composed onto the actions row. */
+  className?: string | undefined
+}
+
+/**
+ * Copy / branch (/ clock) IconActions row shared by user and assistant chrome.
+ * @param props - Copy text, event time, clock side, optional edit, className.
+ * @returns The actions row element.
+ */
+export function MessageIconActions({
+  text, time, clock, edit, className,
+}: MessageIconActionsProps) {
+  const day = useCalendarDay()
+  const onCopy = useCallback(() => {
+    void writeClipboard(text)
+  }, [text])
+  const clockEl = (
+    <span className={clock === 'start' ? css.timeStart : css.timeEnd}>
+      {formatMessageClock(time, day)}
+    </span>
+  )
+  return (
+    <div className={className === undefined ? css.actions : `${css.actions} ${className}`}>
+      {clock === 'start' ? clockEl : null}
+      <Tooltip label="复制" side="bottom">
+        <button type="button" className={css.action} aria-label="复制" onClick={onCopy}>
+          <IconCopyOutline16 />
+        </button>
+      </Tooltip>
+      <Tooltip label="在新对话中分支" side="bottom">
+        <button type="button" className={css.action} aria-label="在新对话中分支">
+          <IconBranchOutline16 />
+        </button>
+      </Tooltip>
+      {edit === true && (
+        <Tooltip label="编辑" side="bottom">
+          <button type="button" className={css.action} aria-label="编辑">
+            <IconEditOutline16 />
+          </button>
+        </Tooltip>
+      )}
+      {clock === 'end' ? clockEl : null}
+    </div>
+  )
+}
--- a/packages/client/ui-conversation/src/client/chat/MessageItem.module.css
+++ b/packages/client/ui-conversation/src/client/chat/MessageItem.module.css
@@ -20,46 +20,14 @@
  color: var(--dsw-alias-label-primary);
 }

-.actions {
-  display: flex;
-  align-items: center;
-  gap: 10px;
-  height: 28px;
-}
-
-/* Hover-capable pointers: hide until the row is hovered/focused. Touch /
-   hover:none keeps actions visible (opacity:0 still hit-tests). */
+/* Hover-capable pointers: reveal shared MessageIconActions on row hover/focus. */
@media (hover: hover) {
-  .actions {
-    opacity: 0;
-    transition: opacity var(--ds-transition-duration) var(--ds-ease-in-out);
-  }
-
  .userRow:hover .actions,
  .userRow:focus-within .actions {
    opacity: 1;
  }
 }

-.action {
-  display: inline-flex;
-  align-items: center;
-  justify-content: center;
-  width: 28px;
-  height: 28px;
-  padding: 6px;
-  border: none;
-  border-radius: 28px;
-  background: transparent;
-  color: var(--dsw-alias-label-tertiary);
-  cursor: pointer;
-}
-
-.action:hover {
-  background: var(--dsw-alias-interactive-bg-hover);
-  color: var(--dsw-alias-label-secondary);
-}
-
 .badge {
  display: inline-block;
  margin-bottom: 4px;
--- a/packages/client/ui-conversation/src/client/chat/MessageItem.tsx
+++ b/packages/client/ui-conversation/src/client/chat/MessageItem.tsx
@@ -1,18 +1,16 @@
 // MessageItem: the four simple node kinds — user bubble (right-aligned, with
-// copy / branch / edit IconActions), steering (badged bubble), context
+// clock + copy / branch / edit IconActions), steering (badged bubble), context
 // injection and unknown-surface JSON rows. Props are frozen node slices off
 // the snapshot cache; memo holds across streaming because unchanged nodes
 // keep their references.

-import { memo, useCallback } from 'react'
+import { memo } from 'react'
 import type { ReactNode } from 'react'
 import type {
  ContextMessageNode, SteeringMessageNode, UnknownSurfaceNode, UserMessageNode,
 } from '@deepseek-ai/dsh-client-runtime/client'
-import {
-  IconBranchOutline16, IconCopyOutline16, IconEditOutline16,
-  JsonBlock, MessageText, Tooltip,
-} from '@deepseek-ai/dsh-client-ui-primitives'
+import { JsonBlock, MessageText } from '@deepseek-ai/dsh-client-ui-primitives'
+import { MessageIconActions } from './MessageIconActions.tsx'
 import css from './MessageItem.module.css'

 export interface MessageItemProps {
@@ -30,42 +28,6 @@ function contentText(content: readonly unknown[]): { text: string; rest: unknown
  return { text: texts.join(''), rest }
 }

-/** Best-effort clipboard write; rejections stay swallowed (no success chrome). */
-async function writeClipboard(text: string): Promise<void> {
-  // lib.dom types clipboard non-optional, but insecure contexts omit it —
-  // that runtime gap is exactly what this guard detects.
-  /* eslint-disable-next-line @typescript-eslint/no-unnecessary-condition */
-  if (navigator.clipboard?.writeText) {
-    try {
-      await navigator.clipboard.writeText(text)
-    } catch {
-      // Denied permissions / iframe policy.
-    }
-    return
-  }
-  // execCommand('copy') is the only clipboard fallback where the async API
-  // is missing (insecure contexts); deprecated but deliberately retained.
-  /* eslint-disable @typescript-eslint/no-deprecated */
-  const exec = typeof document.execCommand === 'function'
-    ? document.execCommand.bind(document)
-    : undefined
-  if (exec === undefined) return
-  const el = document.createElement('textarea')
-  el.value = text
-  el.setAttribute('readonly', '')
-  el.style.position = 'fixed'
-  el.style.left = '-9999px'
-  document.body.appendChild(el)
-  el.select()
-  try {
-    exec('copy')
-  } catch {
-    // Clipboard unavailable; the button stays idle.
-  }
-  /* eslint-enable @typescript-eslint/no-deprecated */
-  el.remove()
-}
-
 /**
 * Display projection of reference forms in a user bubble (free geometry — no
 * textarea alignment constraint here); everything else stays plain text. The
@@ -98,32 +60,6 @@ function projectUserText(text: string): ReactNode {
  return <>{parts}</>
 }

-/** User-bubble IconActions (figma 659:38820): copy is live; branch/edit are chrome stubs. */
-function UserActions({ text }: { text: string }) {
-  const onCopy = useCallback(() => {
-    void writeClipboard(text)
-  }, [text])
-  return (
-    <div className={css.actions}>
-      <Tooltip label="复制" side="bottom">
-        <button type="button" className={css.action} aria-label="复制" onClick={onCopy}>
-          <IconCopyOutline16 />
-        </button>
-      </Tooltip>
-      <Tooltip label="在新对话中分支" side="bottom">
-        <button type="button" className={css.action} aria-label="在新对话中分支">
-          <IconBranchOutline16 />
-        </button>
-      </Tooltip>
-      <Tooltip label="编辑" side="bottom">
-        <button type="button" className={css.action} aria-label="编辑">
-          <IconEditOutline16 />
-        </button>
-      </Tooltip>
-    </div>
-  )
-}
-
 export const MessageItem = memo(function MessageItem({ node }: MessageItemProps) {
  switch (node.kind) {
    case 'user': {
@@ -134,7 +70,13 @@ export const MessageItem = memo(function MessageItem({ node }: MessageItemProps)
            {projectUserText(text)}
            {rest.map((block, i) => <JsonBlock key={i} label="附加内容块" payload={block} />)}
          </div>
-          <UserActions text={text} />
+          <MessageIconActions
+            text={text}
+            time={node.time}
+            clock="start"
+            edit
+            className={css.actions}
+          />
        </div>
      )
    }
--- a/packages/client/ui-conversation/src/client/chat/message-chrome.ts
+++ b/packages/client/ui-conversation/src/client/chat/message-chrome.ts
@@ -0,0 +1,91 @@
+// Shared chrome helpers for user/assistant IconActions rows: clipboard write
+// and the compact date+clock label from a session-event epoch.
+
+/**
+ * Best-effort clipboard write; rejections stay swallowed (no success chrome).
+ * @param text - Plain text to place on the clipboard.
+ */
+export async function writeClipboard(text: string): Promise<void> {
+  // lib.dom types clipboard non-optional, but insecure contexts omit it —
+  // that runtime gap is exactly what this guard detects.
+  /* eslint-disable-next-line @typescript-eslint/no-unnecessary-condition */
+  if (navigator.clipboard?.writeText) {
+    try {
+      await navigator.clipboard.writeText(text)
+    } catch {
+      // Denied permissions / iframe policy.
+    }
+    return
+  }
+  // execCommand('copy') is the only clipboard fallback where the async API
+  // is missing (insecure contexts); deprecated but deliberately retained.
+  /* eslint-disable @typescript-eslint/no-deprecated */
+  const exec = typeof document.execCommand === 'function'
+    ? document.execCommand.bind(document)
+    : undefined
+  if (exec === undefined) return
+  const el = document.createElement('textarea')
+  el.value = text
+  el.setAttribute('readonly', '')
+  el.style.position = 'fixed'
+  el.style.left = '-9999px'
+  document.body.appendChild(el)
+  el.select()
+  try {
+    exec('copy')
+  } catch {
+    // Clipboard unavailable; the button stays idle.
+  }
+  /* eslint-enable @typescript-eslint/no-deprecated */
+  el.remove()
+}
+
+function pad2(n: number): string {
+  return String(n).padStart(2, '0')
+}
+
+/**
+ * Local calendar-day epoch (ms at local midnight) for an instant.
+ * @param ms - Unix epoch ms.
+ * @returns Midnight of that local calendar day.
+ */
+export function startOfLocalDay(ms: number): number {
+  const d = new Date(ms)
+  d.setHours(0, 0, 0, 0)
+  return d.getTime()
+}
+
+/**
+ * Delay until the next local midnight after `ms` (at least 1ms).
+ * @param ms - Unix epoch ms.
+ * @returns Milliseconds until the following local midnight.
+ */
+export function msUntilNextLocalMidnight(ms: number): number {
+  const next = new Date(ms)
+  next.setHours(24, 0, 0, 0)
+  return Math.max(next.getTime() - ms, 1)
+}
+
+/**
+ * Compact local timestamp for message IconActions.
+ * Same calendar day → `HH:mm`; earlier this year → `M月D日 HH:mm`;
+ * other years → `YYYY年M月D日 HH:mm`.
+ * @param time - Unix epoch ms from the source session event.
+ * @param now - Reference instant for the day/year cut (defaults to wall clock).
+ * @returns Date-aware clock string (24-hour, zero-padded time).
+ */
+export function formatMessageClock(time: number, now: number = Date.now()): string {
+  const d = new Date(time)
+  const n = new Date(now)
+  const clock = `${pad2(d.getHours())}:${pad2(d.getMinutes())}`
+  if (
+    d.getFullYear() === n.getFullYear()
+    && d.getMonth() === n.getMonth()
+    && d.getDate() === n.getDate()
+  ) {
+    return clock
+  }
+  const md = `${d.getMonth() + 1}月${d.getDate()}日`
+  if (d.getFullYear() === n.getFullYear()) return `${md} ${clock}`
+  return `${d.getFullYear()}年${md} ${clock}`
+}
--- a/packages/client/ui-conversation/src/client/chat/use-calendar-day.ts
+++ b/packages/client/ui-conversation/src/client/chat/use-calendar-day.ts
@@ -0,0 +1,25 @@
+// Component-local calendar-day tick: memoized message rows keep stable props
+// across midnight, so the IconActions clock needs a local day seat that
+// re-fires at the next local midnight without reaching for framework hooks.
+
+import { useEffect, useState } from 'react'
+import { msUntilNextLocalMidnight, startOfLocalDay } from './message-chrome.ts'
+
+/**
+ * Local calendar-day epoch that advances at each local midnight.
+ * @returns Midnight ms for the current local day; updates after the boundary.
+ */
+export function useCalendarDay(): number {
+  const [day, setDay] = useState(() => startOfLocalDay(Date.now()))
+  useEffect(() => {
+    let timer: ReturnType<typeof setTimeout>
+    const arm = (): void => {
+      const now = Date.now()
+      setDay(startOfLocalDay(now))
+      timer = setTimeout(arm, msUntilNextLocalMidnight(now))
+    }
+    timer = setTimeout(arm, msUntilNextLocalMidnight(Date.now()))
+    return () => { clearTimeout(timer) }
+  }, [])
+  return day
+}
--- a/packages/client/ui-conversation/tests/chat-branch-tails.spec.tsx
+++ b/packages/client/ui-conversation/tests/chat-branch-tails.spec.tsx
@@ -5,9 +5,12 @@
 // with the keyed-slot machinery specs since the tool ring dissolved into
 // renderSlot.)

-import { afterEach, describe, expect, it, vi } from 'vitest'
-import { cleanup, fireEvent, render, screen } from '@testing-library/react'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { act, cleanup, fireEvent, render, screen } from '@testing-library/react'
 import { bindSnapshotSelector } from '@deepseek-ai/dsh-client-web-react'
+import {
+  formatMessageClock, msUntilNextLocalMidnight, startOfLocalDay,
+} from '../src/client/chat/message-chrome.ts'
 import { MessageItem } from '../src/client/chat/MessageItem.tsx'
 import { AssistantMarkdown } from '../src/client/chat/AssistantMarkdown.tsx'
 import { StatsLine, type StatsLineProps } from '../src/client/chat/StatsLine.tsx'
@@ -15,19 +18,24 @@ import { StatsLine, type StatsLineProps } from '../src/client/chat/StatsLine.tsx
 afterEach(cleanup)

 describe('MessageItem arms', () => {
-  it('user bubbles expose copy / branch / edit actions; copy writes the text', () => {
+  it('user bubbles expose clock / copy / branch / edit; copy writes the text', () => {
    const writeText = vi.fn().mockResolvedValue(undefined)
    Object.defineProperty(navigator, 'clipboard', {
      configurable: true,
      value: { writeText },
    })
+    // Same-day clock: construct "today at 14:24" so the label stays `HH:mm`.
+    const now = new Date()
+    const time = new Date(now.getFullYear(), now.getMonth(), now.getDate(), 14, 24).getTime()
    render(
      <MessageItem node={{
-        kind: 'user', seq: 1,
+        kind: 'user', seq: 1, time,
        content: [{ type: 'text', text: 'hello bubble' }] as never,
-      } as never}
+        source: null,
+      }}
      />,
    )
+    expect(screen.getByText('14:24')).toBeTruthy()
    expect(screen.getByRole('button', { name: '复制' })).toBeTruthy()
    expect(screen.getByRole('button', { name: '在新对话中分支' })).toBeTruthy()
    expect(screen.getByRole('button', { name: '编辑' })).toBeTruthy()
@@ -47,9 +55,10 @@ describe('MessageItem arms', () => {
    })
    render(
      <MessageItem node={{
-        kind: 'user', seq: 1,
+        kind: 'user', seq: 1, time: 1_000,
        content: [{ type: 'text', text: 'fallback body' }] as never,
-      } as never}
+        source: null,
+      }}
      />,
    )
    fireEvent.click(screen.getByRole('button', { name: '复制' }))
@@ -69,9 +78,10 @@ describe('MessageItem arms', () => {
    })
    render(
      <MessageItem node={{
-        kind: 'user', seq: 1,
+        kind: 'user', seq: 1, time: 1_000,
        content: [{ type: 'text', text: 'quiet' }] as never,
-      } as never}
+        source: null,
+      }}
      />,
    )
    fireEvent.click(screen.getByRole('button', { name: '复制' }))
@@ -109,6 +119,56 @@ describe('MessageItem arms', () => {
  })
 })

+describe('formatMessageClock', () => {
+  const now = new Date(2026, 6, 29, 10, 0).getTime()
+
+  it('keeps HH:mm on the same calendar day', () => {
+    expect(formatMessageClock(new Date(2026, 6, 29, 14, 24).getTime(), now)).toBe('14:24')
+  })
+
+  it('prefixes month and day across days in the same year', () => {
+    expect(formatMessageClock(new Date(2026, 0, 1, 14, 24).getTime(), now)).toBe('1月1日 14:24')
+  })
+
+  it('prefixes year, month, and day across years', () => {
+    expect(formatMessageClock(new Date(2025, 11, 31, 9, 5).getTime(), now)).toBe('2025年12月31日 09:05')
+  })
+
+  it('arms the next local midnight from an in-day instant', () => {
+    const noon = new Date(2026, 6, 29, 12, 0).getTime()
+    expect(startOfLocalDay(noon)).toBe(new Date(2026, 6, 29).getTime())
+    expect(msUntilNextLocalMidnight(noon)).toBe(12 * 3_600_000)
+  })
+})
+
+describe('useCalendarDay boundary refresh', () => {
+  beforeEach(() => {
+    vi.useFakeTimers()
+  })
+  afterEach(() => {
+    vi.useRealTimers()
+  })
+
+  it('widens a same-day user clock after local midnight', () => {
+    const dayStart = new Date(2026, 6, 29, 23, 50).getTime()
+    vi.setSystemTime(dayStart)
+    const time = new Date(2026, 6, 29, 14, 24).getTime()
+    render(
+      <MessageItem node={{
+        kind: 'user', seq: 1, time,
+        content: [{ type: 'text', text: 'night bubble' }] as never,
+        source: null,
+      }}
+      />,
+    )
+    expect(screen.getByText('14:24')).toBeTruthy()
+    act(() => {
+      vi.advanceTimersByTime(msUntilNextLocalMidnight(dayStart) + 1)
+    })
+    expect(screen.getByText('7月29日 14:24')).toBeTruthy()
+  })
+})
+
 describe('small branch tails', () => {
  it('AssistantMarkdown single-line reasoning summary skips the newline cut', () => {
    const view = render(
@@ -117,6 +177,35 @@ describe('small branch tails', () => {
    expect(view.getByText('one-liner')).toBeTruthy()
  })

+  it('finalized assistant messages expose copy / branch / clock after the body; streaming omits them', () => {
+    const writeText = vi.fn().mockResolvedValue(undefined)
+    Object.defineProperty(navigator, 'clipboard', {
+      configurable: true,
+      value: { writeText },
+    })
+    const now = new Date()
+    const time = new Date(now.getFullYear(), now.getMonth(), now.getDate(), 14, 24).getTime()
+    const settled = render(
+      <AssistantMarkdown
+        blocks={[{ kind: 'text', text: 'answer body' }, { kind: 'reasoning', text: 'hidden' }]}
+        streaming={false}
+        time={time}
+      />,
+    )
+    expect(settled.getByText('14:24')).toBeTruthy()
+    expect(settled.getByRole('button', { name: '复制' })).toBeTruthy()
+    expect(settled.getByRole('button', { name: '在新对话中分支' })).toBeTruthy()
+    fireEvent.click(settled.getByRole('button', { name: '复制' }))
+    expect(writeText).toHaveBeenCalledWith('answer body')
+    settled.unmount()
+
+    const streaming = render(
+      <AssistantMarkdown blocks={[{ kind: 'text', text: 'partial' }]} streaming time={time} />,
+    )
+    expect(streaming.queryByRole('button', { name: '复制' })).toBeNull()
+    expect(streaming.queryByText('14:24')).toBeNull()
+  })
+
  it('StatsLine omits the cache-hit segment when no input accounting exists at all', () => {
    const snap = {
      nodes: [{ kind: 'assistant', seq: 1, turn: 1, step: 1, blocks: [], usage: { outputTokens: 10 } }],
--- a/packages/client/ui-layout/README.i18n.yaml
+++ b/packages/client/ui-layout/README.i18n.yaml
@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/client/ui-layout/README.md
-README.md: 26e909b96412985792eeae72d51a2ab2a315c943
-README.zh.md: 2e5799fd32c41328f8ca8b9e1a439fbccb3cdba2
+README.md: 9354f4b79f7b1af7d8a20a295e77913ff443c2e4
+README.zh.md: c949236557e7eb3eed0c698566fb5aa9e9cdd18a
--- a/packages/client/ui-layout/README.md
+++ b/packages/client/ui-layout/README.md
@@ -4,7 +4,7 @@ English | [中文](README.zh.md)

 Shell plugin: three-column AppFrame (drag handles and concession chain) plus the `ctx.layout` panel-geometry service; it registers into the runtime-owned `root` slot and declares `sidebar`, `conversation`, `details`, and `conversation.empty`. The sidebar is fixed-width (only details shrinks, then auto-closes); a closed sidebar retains a 56px control rail while details closes to zero width. The package also seats the theme presenter: it consumes resolved `ctx.theme` snapshots and projects them onto the document (`html { color-scheme }` for native UA chrome, `body[data-ds-dark-theme]` from the active color scheme, plus the theme's alias tokens as inline variables on body).

-AppFrame reads the runtime Session projection: `baselinesReady` selects loading, a page-local `SessionListState.intent` selects the empty composer, and a connected Session renders through `SessionProvider`. The conversation and empty-state owner shares are empty; each registrant obtains business data from standard hooks and actions from its own inject face. The sidebar owner share contains only `collapsed` and `width`; navigation actions belong to sidebar's own injected service face.
+AppFrame always mounts the conversation and details columns; a connected Session renders through `SessionProvider`. The transient layout store starts both panels at their default widths and never reads or writes `localStorage`. Hero and other unselected states derive a zero rendered details width without changing that stored preference. AppFrame retains the last non-blank Session id across those states: the first Session opens at the default width, returning to the same Session restores its unchanged width, and selecting a different Session closes details before paint. The conversation owner share is empty, while the sidebar owner share contains only `collapsed` and `width`; registrants obtain business data from standard hooks and actions from their own inject faces.

 The `/client` export surface is the plugin body (`apply`/`inject`), `LayoutService`, and the four owner-share interfaces. AppFrame, the panel store, and the concession solver remain package-internal; tests import internals through `/src`.

@@ -18,6 +18,6 @@ None; this package neither assembles nor sends a provider request.

 ## Known Limitations and Deferred Work

- **Details open/width state is global** — it does not follow the session (arbitrated for P-I); the per-session keyed upgrade slot is reserved.
- **Concession-chain auto-close derives a zero width without touching the persisted open flag** — the panel restores itself when the window widens; consumers must not read `details.open` as the rendered truth.
+- **Panel geometry is transient** — reload restores both panels to their defaults; switching between distinct Session ids closes details and forgets its dragged width, while unselected surfaces render details at zero width without modifying geometry.
+- **Concession-chain auto-close derives a zero width without touching the preferred width** — the panel restores itself when the window widens; consumers must not read the stored details width as the rendered truth.
 - **Scroll anchoring during squeeze reflow is not implemented** — deferred with the virtualized-list project.
--- a/packages/client/ui-layout/README.zh.md
+++ b/packages/client/ui-layout/README.zh.md
@@ -4,7 +4,7 @@

 外壳插件：三栏 AppFrame（拖动手柄与让步链）加 `ctx.layout` 面板几何服务；它注册到运行时拥有的 `root` slot，并声明 `sidebar`、`conversation`、`details` 和 `conversation.empty`。侧边栏宽度固定（只会收缩详情栏，然后将其自动关闭）；关闭的侧边栏仍保留 56px 控制轨道，详情栏则关闭到零宽度。该包还提供主题呈现器：它消费解析后的 `ctx.theme` 快照，并将其投影到 document（用 `html { color-scheme }` 驱动原生 UA 控件，依据当前配色方案设置 `body[data-ds-dark-theme]`，并将主题的别名 token 设为 body 上的内联变量）。

-AppFrame 读取运行时 Session 投影：`baselinesReady` 选择加载状态，页面局部的 `SessionListState.intent` 选择空白编辑器，已连接 Session 则通过 `SessionProvider` 渲染。会话及空状态的 owner share 为空；每个注册方通过标准 hook 获取业务数据，并从自身的 inject 表层获取操作。侧边栏 owner share 只包含 `collapsed` 和 `width`；导航操作属于侧边栏自身注入的服务表层。
+AppFrame 始终挂载会话栏和详情栏；已连接 Session 通过 `SessionProvider` 渲染。布局 store 是瞬时状态，两个面板均以默认宽度启动，且从不读写 `localStorage`。hero 和其他未选中状态会将详情栏的渲染宽度派生为零，但不会改变存储的首选宽度。AppFrame 会跨越这些状态保留最后一个非 blank 会话 id：首个会话以默认宽度打开；返回同一会话时恢复其未改变的宽度；选择不同会话时，详情栏会在绘制前关闭。会话 owner share 为空，侧边栏 owner share 只包含 `collapsed` 和 `width`；注册方通过标准钩子获取业务数据，并从各自的 inject 表层获取操作。

 `/client` 导出表层包含插件主体（`apply`／`inject`）、`LayoutService` 和四个 owner-share 接口。AppFrame、面板 store 与让步求解器仍属于包内部；测试通过 `/src` 导入内部实现。

@@ -18,6 +18,6 @@ AppFrame 读取运行时 Session 投影：`baselinesReady` 选择加载状态，

 ## 已知限制与暂缓事项

- **详情栏打开／宽度状态是全局状态**：它不会随会话变化（P-I 已裁定）；为逐会话键控升级预留了 slot。
- **让步链自动关闭通过推导零宽度实现，不会改动持久化的打开标志**：窗口变宽时面板会自行恢复；消费方禁止把 `details.open` 当作实际渲染状态。
+- **面板几何信息是瞬时状态**：重新加载会将两个面板恢复为默认值；在不同会话 id 之间切换会关闭详情栏，并忘记拖动后的宽度，而未选中表面会以零宽度渲染详情栏，但不会修改几何信息。
+- **让步链自动关闭通过推导零宽度实现，不会改动首选宽度**：窗口变宽时面板会自行恢复；消费方禁止把 store 中的详情宽度当作实际渲染状态。
 - **挤压重排期间尚未实现滚动锚定**：与虚拟化列表项目一并暂缓。
--- a/packages/client/ui-layout/src/client/AppFrame.tsx
+++ b/packages/client/ui-layout/src/client/AppFrame.tsx
@@ -10,7 +10,7 @@
 * through the three framework shares — zero cordis or framework imports,
 * zero self-made hooks.
 */
-import { useCallback, useEffect, useRef, useState } from 'react'
+import { useCallback, useEffect, useLayoutEffect, useRef, useState } from 'react'
 import type { ReactNode } from 'react'
 import type { PropsRenderSlots, PropsRuntime, PropsStore } from '@deepseek-ai/dsh-client-ui-slots'
 import { computeColumns } from './columns.ts'
@@ -86,13 +86,27 @@ function DragHandle(props: { side: 'sidebar' | 'details'; left: number; onStart:
 /** The three-column frame (see module doc). */
 export function AppFrame({
  useStore,
+  useSessions,
  actions,
  renderSlot,
 }: AppFrameProps) {
  const panels = useStore(s => s)
+  const detailsSession = useSessions((s) => {
+    const current = s.current
+    return current !== undefined && s.byId[current]?.blank === false ? current : undefined
+  })
  const frameRef = useRef<HTMLDivElement | null>(null)
  const [viewport, setViewport] = useState(() => window.innerWidth)

+  const lastSession = useRef(detailsSession)
+  useLayoutEffect(() => {
+    if (detailsSession === undefined) return
+    if (lastSession.current !== undefined && lastSession.current !== detailsSession) {
+      actions.closeDetails()
+    }
+    lastSession.current = detailsSession
+  }, [actions, detailsSession])
+
  // Track the frame's own box (not the window): rAF-throttled ResizeObserver.
  useEffect(() => {
    const el = frameRef.current
@@ -113,12 +127,12 @@ export function AppFrame({
    }
  }, [])

-  const cols = computeColumns(viewport, panels.sidebar, panels.details)
+  const cols = computeColumns(viewport, panels.sidebar, detailsSession === undefined ? 0 : panels.details)
  const colsRef = useRef(cols)
  colsRef.current = cols

  // The drag base is the rendered width captured at drag start (grabbing a
-  // concession-clamped panel must not jump back to the persisted preference);
+  // concession-clamped panel must not jump back to the stored preference);
  // it stays frozen for the whole gesture so dx deltas do not compound.
  const sidebarBase = useRef(0)
  const detailsBase = useRef(0)
--- a/packages/client/ui-layout/src/client/columns.ts
+++ b/packages/client/ui-layout/src/client/columns.ts
@@ -1,7 +1,7 @@
 /**
 * Pure concession-chain column solver for the three-column AppFrame.
 * Chain order is fixed by contract: keep center >= CENTER_MIN by shrinking
- * details, then auto-closing it (derived zero width — persisted width
+ * details, then auto-closing it (derived zero width — preferred width
 * preferences are never rewritten, so widening the window restores them).
 * The sidebar never concedes: its rendered width is always the drag
 * preference (or the collapsed rail), and center absorbs any remaining
@@ -45,8 +45,8 @@ export function clampWidth(px: number, min: number, max: number): number {
 /**
 * Solve the three column widths for one viewport frame. Pure: no hysteresis —
 * the output is a function of (viewport, preferences) only, so recovery on
- * re-widening is automatic. Preferences re-clamp here because they cross a
- * durable boundary (localStorage rehydration may carry stale ranges).
+ * re-widening is automatic. Preferences re-clamp here because they cross the
+ * store boundary and callers may still supply stale ranges.
 * @param viewport - available frame width in px.
 * @param sidebar - sidebar width preference in px (0 = closed).
 * @param details - details width preference in px (0 = closed).
--- a/packages/client/ui-layout/src/client/stores.ts
+++ b/packages/client/ui-layout/src/client/stores.ts
@@ -1,7 +1,7 @@
 /**
- * The root entry's layout store: panel geometry as plain widths in px
- * (0 = closed), persisted across reloads. Module level exports the factory
- * only — a module-level handle would pin the store's identity in the module
+ * The root entry's transient layout store: panel geometry as plain widths in
+ * px (0 = closed). Module level exports the factory only — a module-level
+ * handle would pin the store's identity in the module
 * cache (a de-facto singleton surviving plugin reloads). register() receives
 * the factory (exclusive use: the framework instantiates per entry), AppFrame
 * derives its PropsStore share from the return type, and the service face
@@ -29,17 +29,16 @@ type LayoutActions = {
 }

 /**
- * Create the layout panel store handle. The persisted preference IS the
- * width, so closing a panel forgets its drag width — reopening restores the
- * contract default. Actions are the complete write set: drag writes clamp
+ * Create the layout panel store handle. The preference IS the width, so
+ * closing a panel forgets its drag width — reopening restores the contract
+ * default. Actions are the complete write set: drag writes clamp
 * into the panel's contract range and never cross the open/closed line;
 * open/close transitions write 0 / the default explicitly.
 * @returns the store handle (spec + type + identity + factory in one).
 */
 export function createLayoutStore(): EngineStoreHandle<LayoutState, LayoutActions>  {
  const handle = defineStore({
-    init: (): LayoutState => ({ sidebar: SIDEBAR_DEFAULT, details: 0 }),
-    persist: 'dsh.layout.panels',
+    init: (): LayoutState => ({ sidebar: SIDEBAR_DEFAULT, details: DETAILS_DEFAULT }),
    actions: {
      setSidebar: (d, px: number) => { d.sidebar = clampWidth(px, SIDEBAR_MIN, SIDEBAR_MAX) },
      setDetails: (d, px: number) => { d.details = clampWidth(px, DETAILS_MIN, DETAILS_MAX) },
--- a/packages/client/ui-layout/src/invariant.ts
+++ b/packages/client/ui-layout/src/invariant.ts
@@ -15,8 +15,8 @@ export const name = 'client-ui-layout-invariant'
 export const inject = ['invariants']

 /**
- * No runtime invariant: shell viewing-state stores (zustand+persist) behind
- * ctx.layout — it emits no cordis events; clamp/prune/concession-chain
+ * No runtime invariant: the shell viewing-state store behind ctx.layout emits
+ * no cordis events; clamp/prune/concession-chain
 * sequencing is asserted directly by this package's columns and service specs.
 */
 const install: InvariantInstaller = () => {}
--- a/packages/client/ui-layout/tests/app-frame.spec.tsx
+++ b/packages/client/ui-layout/tests/app-frame.spec.tsx
@@ -21,8 +21,9 @@ import type {
  SessionId, SessionListState, WorkspaceListState,
 } from '@deepseek-ai/dsh-client-runtime/client'

-// Session-mode switch for the SessionProvider stub prop.
-const sessionMode = { current: true }
+// Session selection controls for the SessionProvider and useSessions stubs.
+const selectedSession = { current: 's-test' as SessionId | undefined }
+const selectedSessionBlank = { current: false }
 const baselinesReady = { current: true }

 // Render-prop contract stub fed through the standard seat prop (the renderer
@@ -31,7 +32,7 @@ const baselinesReady = { current: true }
 // shape. Typed as the seat's own component type so the branded sessionId
 // parameter stays contract-checked.
 const SessionProviderStub: AppFrameProps['SessionProvider'] = ({ children, empty }) =>
-  sessionMode.current ? <>{children('s-test' as Parameters<typeof children>[0])}</> : <>{empty?.() ?? null}</>
+  selectedSession.current === undefined ? <>{empty?.() ?? null}</> : <>{children(selectedSession.current)}</>


 /** Observer stub: captures the callback so tests can fire resizes manually. */
@@ -54,7 +55,6 @@ function hookOf<T>(inst: { subscribe: (fn: () => void) => () => void; getSnapsho
 function mountFrame() {
  window.innerWidth = frameWidth // first-render viewport source before the observer fires
  const instance = createLayoutStore().create()
-  instance.actions.openDetails() // seed: sidebar at default 280, details open at default 360
  const slotCalls: { key: string; props: unknown }[] = []
  const renderSlot = ((key: string, owner: object) => {
    slotCalls.push({ key, props: owner })
@@ -64,32 +64,35 @@ function mountFrame() {
    if (key === 'conversation.empty') return <div data-testid="empty-content" />
    return <div data-testid="other-content" />
  }) as AppFrameProps['renderSlot']
-  const sessionId = 's-test' as SessionId
-  const sessionState = {
-    ids: sessionMode.current ? [sessionId] : [],
-    byId: sessionMode.current
-      ? { [sessionId]: { id: sessionId, displayTitle: 'Test', running: false, blank: false, updatedAt: 1 } }
-      : {},
-    current: sessionMode.current ? sessionId : undefined,
-    phase: 'ready',
-  } as SessionListState
-  const useSessions = ((sel: (s: SessionListState) => unknown) => sel(sessionState)) as never
+  const useSessions = ((sel: (s: SessionListState) => unknown) => {
+    const current = selectedSession.current
+    const sessionState = {
+      ids: current === undefined ? [] : [current],
+      byId: current === undefined
+        ? {}
+        : { [current]: { id: current, displayTitle: 'Test', running: false, blank: selectedSessionBlank.current, updatedAt: 1 } },
+      current,
+      phase: 'ready',
+    } as SessionListState
+    return sel(sessionState)
+  }) as never
  const workspaceState: WorkspaceListState = {
    items: [], state: 'idle', phase: 'ready', error: null,
    baselinesReady: baselinesReady.current, recentWorkspaceId: undefined,
  }
-  const utils = render(
+  const element = () => (
    <AppFrame
-      useStore={hookOf(instance) as never}
+      useStore={hookOf(instance)}
      actions={instance.actions}
      renderSlot={renderSlot}
      useSessions={useSessions}
      useWorkspaces={((sel: (s: WorkspaceListState) => unknown) => sel(workspaceState)) as never}
      SessionProvider={SessionProviderStub}
-    />,
+    />
  )
+  const utils = render(element())
  const frame = utils.container.firstElementChild as HTMLElement
-  return { instance, frame, slotCalls, ...utils }
+  return { instance, frame, slotCalls, rerenderFrame: () => { utils.rerender(element()) }, ...utils }
 }

 function tracks(frame: HTMLElement): number[] {
@@ -109,9 +112,9 @@ function drag(handle: Element, fromX: number, toX: number): void {

 beforeEach(() => {
  frameWidth = 1920
-  sessionMode.current = true
+  selectedSession.current = 's-test' as SessionId
+  selectedSessionBlank.current = false
  baselinesReady.current = true
-  localStorage.clear() // the layout store persists; instances must not bleed across tests
  vi.useFakeTimers()
  vi.stubGlobal('ResizeObserver', ResizeObserverStub)
  vi.stubGlobal('requestAnimationFrame', (cb: FrameRequestCallback) => setTimeout(() => { cb(0) }, 16) as unknown as number)
@@ -154,7 +157,7 @@ describe('AppFrame', () => {
  it('keeps the conversation slot mounted while no session is current', () => {
    // No current session: the session-maybe conversation shell owns the New
    // Session view itself — the center column renders it unconditionally.
-    sessionMode.current = false
+    selectedSession.current = undefined
    const { slotCalls, getByTestId } = mountFrame()
    expect(getByTestId('center-content')).toBeTruthy()
    expect(slotCalls.map(c => c.key)).toContain('conversation')
@@ -169,6 +172,45 @@ describe('AppFrame', () => {
    expect(slotCalls.map(c => c.key)).toContain('details')
  })

+  it('ignores unselected states and closes only when the Session id changes', () => {
+    const { frame, instance, rerenderFrame } = mountFrame()
+    expect(tracks(frame)).toEqual([280, 360])
+
+    selectedSession.current = 's-next' as SessionId
+    act(() => { rerenderFrame() })
+    expect(tracks(frame)).toEqual([280, 0])
+
+    act(() => { instance.actions.openDetails() })
+    selectedSession.current = 's-blank' as SessionId
+    selectedSessionBlank.current = true
+    act(() => { rerenderFrame() })
+    expect(tracks(frame)).toEqual([280, 0])
+    expect(instance.getSnapshot().details).toBe(360)
+
+    selectedSession.current = 's-next' as SessionId
+    selectedSessionBlank.current = false
+    act(() => { rerenderFrame() })
+    expect(tracks(frame)).toEqual([280, 360])
+
+    selectedSession.current = undefined
+    act(() => { rerenderFrame() })
+    expect(tracks(frame)).toEqual([280, 0])
+    selectedSession.current = 's-test' as SessionId
+    act(() => { rerenderFrame() })
+    expect(tracks(frame)).toEqual([280, 0])
+  })
+
+  it('keeps the default details width when the first Session materializes', () => {
+    selectedSession.current = undefined
+    const { frame, instance, rerenderFrame } = mountFrame()
+    expect(tracks(frame)).toEqual([280, 0])
+    expect(instance.getSnapshot().details).toBe(360)
+
+    selectedSession.current = 's-first' as SessionId
+    act(() => { rerenderFrame() })
+    expect(tracks(frame)).toEqual([280, 360])
+  })
+
  it('sidebar slot receives live concession output as owner props', () => {
    const { slotCalls } = mountFrame()
    expect(slotCalls.find(c => c.key === 'sidebar')!.props).toEqual({ collapsed: false, width: 280 })
--- a/packages/client/ui-layout/tests/layout-store.spec.ts
+++ b/packages/client/ui-layout/tests/layout-store.spec.ts
@@ -1,8 +1,8 @@
 // @vitest-environment jsdom
 /**
 * createLayoutStore unit account: init shape, the action write set (clamp
- * inside actions), and the persist key round-trip over jsdom localStorage.
- * Uses the test-sanctioned path: factory self-call + .create() gives the
+ * inside actions), and the absence of browser persistence. Uses the
+ * test-sanctioned path: factory self-call + .create() gives the
 * real engine instance (same create path as production).
 */
 import { beforeEach, describe, expect, it } from 'vitest'
@@ -17,9 +17,9 @@ const PERSIST_KEY = 'dsh.layout.panels'
 beforeEach(() => { localStorage.clear() })

 describe('createLayoutStore', () => {
-  it('initializes with sidebar open at default and details closed', () => {
+  it('initializes both panels at their default widths', () => {
    const { store } = createLayoutStore().create()
-    expect(store.getSnapshot()).toEqual({ sidebar: SIDEBAR_DEFAULT, details: 0 })
+    expect(store.getSnapshot()).toEqual({ sidebar: SIDEBAR_DEFAULT, details: DETAILS_DEFAULT })
  })

  it('each create() is an independent instance (factory is not a singleton)', () => {
@@ -52,6 +52,7 @@ describe('createLayoutStore', () => {

  it('openDetails is a no-op when already open; closeDetails zeroes', () => {
    const { store, actions } = createLayoutStore().create()
+    actions.closeDetails()
    actions.openDetails()
    expect(store.getSnapshot().details).toBe(DETAILS_DEFAULT)
    actions.setDetails(500)
@@ -61,13 +62,16 @@ describe('createLayoutStore', () => {
    expect(store.getSnapshot().details).toBe(0)
  })

-  it('persists under dsh.layout.panels and rehydrates on the next create', () => {
+  it('does not persist panel geometry', () => {
    const first = createLayoutStore().create()
-    first.actions.setSidebar(320)
-    first.actions.openDetails()
-    expect(JSON.parse(localStorage.getItem(PERSIST_KEY) ?? '{}')).toEqual({ sidebar: 320, details: DETAILS_DEFAULT })
+    first.actions.setSidebar(400)
+    first.actions.closeDetails()
+    expect(localStorage.getItem(PERSIST_KEY)).toBeNull()

    const second = createLayoutStore().create()
-    expect(second.store.getSnapshot()).toEqual({ sidebar: 320, details: DETAILS_DEFAULT })
+    expect(second.store.getSnapshot()).toEqual({
+      sidebar: SIDEBAR_DEFAULT,
+      details: DETAILS_DEFAULT,
+    })
  })
 })
--- a/scripts/install-lefthook.mjs
+++ b/scripts/install-lefthook.mjs
@@ -2,7 +2,7 @@
 import { randomUUID } from 'node:crypto'
 import { existsSync, lstatSync, mkdirSync, readdirSync, readFileSync, unlinkSync, writeFileSync } from 'node:fs'
 import { spawnSync } from 'node:child_process'
-import { isAbsolute, join, resolve } from 'node:path'
+import { dirname, isAbsolute, join, resolve } from 'node:path'

 const MINIMUM_GIT = [2, 26, 0]
 const HOOKS_DIRECTORY = 'dsh-hooks'
@@ -437,6 +437,15 @@ function inspectOwnedHooksDirectory(hooksPath) {
  return { markerPath, ...marker }
 }

+function isRegisteredOwnedHooksPath(commonDirectory, hooksPath) {
+  const normalizedHooksPath = normalizedPath(hooksPath)
+  const isRegistered = registeredWorktreeConfigPaths(commonDirectory).some(
+    configPath => normalizedPath(join(dirname(configPath), HOOKS_DIRECTORY)) === normalizedHooksPath,
+  )
+  if (!isRegistered) return false
+  return inspectOwnedHooksDirectory(hooksPath)?.hooksPath === hooksPath
+}
+
 function ensureOwnedHooksDirectory(hooksPath) {
  const inspected = inspectOwnedHooksDirectory(hooksPath)
  if (inspected !== undefined) return inspected
@@ -561,14 +570,22 @@ async function main() {
      'worktree core.hooksPath',
    )
    let ownedHooksDirectory
+    let copiedWorktreePathIsOwned = false
    if (worktreePath !== undefined && worktreePath !== hooksPath) {
      ownedHooksDirectory = inspectOwnedHooksDirectory(hooksPath)
-      if (ownedHooksDirectory === undefined || ownedHooksDirectory.hooksPath !== worktreePath) {
+      const worktreePathIsRelocated = ownedHooksDirectory?.hooksPath === worktreePath
+      copiedWorktreePathIsOwned = !worktreePathIsRelocated
+        && isRegisteredOwnedHooksPath(commonDirectory, worktreePath)
+      if (!worktreePathIsRelocated && !copiedWorktreePathIsOwned) {
        refuseScopedHooksPath({ origin: `file:${worktreeConfigPath}`, scope: 'worktree', value: worktreePath })
      }
    }
    const directWorktreePathIsOwned = worktreePath !== undefined
-      && (worktreePath === hooksPath || ownedHooksDirectory?.hooksPath === worktreePath)
+      && (
+        worktreePath === hooksPath
+        || ownedHooksDirectory?.hooksPath === worktreePath
+        || copiedWorktreePathIsOwned
+      )
    const effectiveEntry = effectiveConfigEntry(root, 'core.hooksPath')
    if (effectiveEntry !== undefined) {
      const effectivePathIsOwned = effectiveEntry.scope === 'worktree'
@@ -593,6 +610,7 @@ async function main() {
      worktreePath !== undefined
      && worktreePath !== hooksPath
      && ownedHooksDirectory.hooksPath !== worktreePath
+      && !copiedWorktreePathIsOwned
    ) {
      throw new Error(`hooks directory ownership changed while relocating ${JSON.stringify(worktreePath)}`)
    }
--- a/scripts/install-lefthook.spec.ts
+++ b/scripts/install-lefthook.spec.ts
@@ -262,6 +262,30 @@ describe('worktree-local Lefthook installer', () => {
    expect(readFileSync(legacyHook, 'utf8')).toBe('#!/bin/sh\n# legacy hook\n')
  })

+  it('replaces the owned hook path Git copies into a newly added worktree', async () => {
+    const fixture = createFixture()
+    const mainInstall = await runInstaller(fixture, fixture.main)
+    expect(mainInstall.status, mainInstall.stderr).toBe(0)
+    const mainHooks = hooksPath(fixture, fixture.main)
+    const mainHookBefore = readFileSync(join(mainHooks, 'pre-commit'), 'utf8')
+    const lateLinked = join(fixture.container, 'late-linked')
+    git(fixture, fixture.main, ['worktree', 'add', '-b', 'late-linked', lateLinked])
+    write(join(lateLinked, 'lefthook.yml'), 'late-linked-worktree-config\n')
+    installFakeLefthook(lateLinked)
+    expect(git(fixture, lateLinked, ['config', '--worktree', '--get', 'core.hooksPath'])).toBe(mainHooks)
+
+    const linkedInstall = await runInstaller(fixture, lateLinked)
+
+    expect(linkedInstall.status, linkedInstall.stderr).toBe(0)
+    const linkedHooks = hooksPath(fixture, lateLinked)
+    expect(linkedHooks).not.toBe(mainHooks)
+    expect(git(fixture, lateLinked, ['config', '--worktree', '--get', 'core.hooksPath'])).toBe(linkedHooks)
+    expect(readFileSync(join(linkedHooks, 'pre-commit'), 'utf8')).toContain(
+      '# config=late-linked-worktree-config',
+    )
+    expect(readFileSync(join(mainHooks, 'pre-commit'), 'utf8')).toBe(mainHookBefore)
+  })
+
  it('serializes concurrent installs and keeps repeated output stable', async () => {
    const fixture = createFixture()
    const delayed = { DSH_TEST_LEFTHOOK_DELAY_MS: '150' }
@@ -509,6 +533,30 @@ describe('worktree-local Lefthook installer', () => {
    expect(git(fixture, fixture.linked, ['config', '--worktree', '--get', 'core.hooksPath'])).toBe('linked-custom-hooks')
  })

+  it('does not trust an ownership marker outside a registered worktree hook path', async () => {
+    const fixture = createFixture()
+    const mainInstall = await runInstaller(fixture, fixture.main)
+    expect(mainInstall.status, mainInstall.stderr).toBe(0)
+    const externalHooks = join(fixture.container, 'external-owned-hooks')
+    write(
+      join(externalHooks, '.dsh-lefthook-owned'),
+      `${JSON.stringify({
+        version: 1,
+        owner: 'deepseek-harness worktree-local lefthook hooks',
+        hooksPath: externalHooks,
+      })}\n`,
+      0o600,
+    )
+    git(fixture, fixture.linked, ['config', '--worktree', 'core.hooksPath', externalHooks])
+
+    const result = await runInstaller(fixture, fixture.linked)
+
+    expect(result.status).toBe(1)
+    expect(result.stderr).toContain('worktree-scoped core.hooksPath')
+    expect(git(fixture, fixture.linked, ['config', '--worktree', '--get', 'core.hooksPath'])).toBe(externalHooks)
+    expect(existsSync(hooksPath(fixture, fixture.linked))).toBe(false)
+  })
+
  it('refuses to activate a sibling worktree dormant hook path', async () => {
    const fixture = createFixture()
    const linkedConfig = join(gitDirectory(fixture, fixture.linked), 'config.worktree')
--- a/scripts/snapshots/translation-prompt-v4/request-response.expected.json
+++ b/scripts/snapshots/translation-prompt-v4/request-response.expected.json
--- a/tsconfig.host.json
+++ b/tsconfig.host.json
@@ -15,6 +15,7 @@
    "apps/web/tests/steering.e2e.ts",
    "apps/web/tests/navigation-panes.e2e.ts",
    "apps/web/tests/lifecycle-chrome.e2e.ts",
+    "apps/web/tests/details-session-lifecycle.e2e.ts",
    "apps/web/tests/settings-chrome.e2e.ts",
    "apps/web/tests/workspace-management.e2e.ts",
    "apps/web/tests/replay-round-trip.e2e.ts",
@@ -22,6 +23,7 @@
    "apps/web/tests/sidebar-scrollbar.e2e.ts",
    "apps/web/tests/code-mode-round.e2e.ts",
    "apps/web/tests/cordis-tool-round.e2e.ts",
+    "apps/web/tests/message-actions.e2e.ts",
    "apps/cli/tests/**/*.ts",
    "examples/*/src/**/*.ts",
    "examples/*/start.ts",