Merge remote-tracking branch 'origin/master' into worktree/persist-web-theme-settings

# Conflicts:
#	packages/client/ui-conversation/README.i18n.yaml
#	packages/host/apiproxy/README.i18n.yaml

.agents/notes/implemented/feature/2026-08-07-default-model-follows-the-picker.i18n.yaml

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+# 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/2026-08-07-default-model-follows-the-picker.md
+2026-08-07-default-model-follows-the-picker.md: d20f0ab8b8c8bd19f596e6ef73f0a58d96c24d38
+2026-08-07-default-model-follows-the-picker.zh.md: 0d2821cb63407fe766e6fe3d36de31d9fc6f1c13

.agents/notes/implemented/feature/2026-08-07-default-model-follows-the-picker.md

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+# Agent Note: the default model follows the picker
+
+Status: implemented
+
+English | [中文](2026-08-07-default-model-follows-the-picker.zh.md)
+
+## Problem
+
+The route a new session started from was frozen into the gateway's composition entry (`api-gateway` in the web-app bundle patch). Switching models in a conversation reached that conversation only: the next session went back to the shipped default, and the only way to change it was to hand-edit a `cordis.yml` row and restart. There was no user-settings tier between the composition and the per-session choice.
+
+## Decision
+
+`ApiProxyService` registers its `{provider, model, reasoningEffort?}` slice as the `api-gateway` settings section: the composition entry is the `base` layer and `settings.yaml` layers the user's choice over it. `workspaceRoot` stays outside the section — a launcher fact, not a preference. `reasoningEffort` is the mirror case: it lives in the section but NOT in the plugin config, because the seam merges the user layer over the composition entry per field and an absent key cannot override a present one. A composition-set effort would therefore survive every later switch to a model without one — precisely the stranding the wholesale `replace` exists to prevent. Effort is a per-model fact anyway; a deployment default for it belongs on the adapter profile, which resolves per model.
+
+`session.selectModel` records an accepted switch as the new default. There is no separate gesture: switching models in the composer IS how the default is chosen. The write is `replace`, not `update` — switching to a model with no reasoning effort has to clear a stored one, and a merged patch would strand it for the next session to fail on. A storage failure is logged without undoing the switch, which already applies to its own session, and a deployment with no settings provider keeps the entry with the switch staying process-local.
+
+`ApiProxyDefaults` carries `defaultTarget()` and `persistDefaultTarget()` closures instead of flat `provider`/`model` fields, so `createApiProxy` needs no knowledge of the settings seam.
+
+`targetFor` resolves its tiers on **every** read rather than seeding a ref once: an explicit selection in this process, else the session's own latest logged `request/header`, else the live default. Both directions depend on the re-read. A session that has run a turn derives from its log forever after, so changing the default never retargets it. A session still blank starts from a default saved after it was created — which matters because New Session reuses a blank session rather than minting another, so a creation-time seed would show the superseded model in exactly the flow the feature exists for.
+
+The stored route is not validated against the registry. A default naming a route the Models page has since removed still reaches `session.models` as `current`, matching no advertised group — which is what makes the composer seat's existing fallback prompt for a selection instead of naming a model the deployment cannot reach.
+
+## Consequences
+
+`ApiProxyDefaults` changed shape, updating ~40 test construction sites. `host.describe` now reports the live default rather than a captured one, which is what it always meant. `settings.yaml` gains an `api-gateway:` section the moment a user switches models; the `api-gateway` namespace is deliberately NOT added to the gateway's exposed-namespace allowlist, so the Settings page neither reads nor writes it — the model picker is its editor.
+
+## Follow-up: blocking a session that cannot send
+
+A default naming a route the Models page has since removed leaves the composer saying "Select model" while the input still accepts a message, which then fails inside the adapter mid-turn. Two changes close it.
+
+The Host refuses. `session.prompt` checks whether an adapter serves the session's route and answers `model-unavailable` before opening a turn. This is the enforcement boundary: a client that disables its composer is an affordance, and the method stays callable regardless.
+
+The composer goes inert. `session.models` reports `routable`, and ui-model pushes a block through the new `ctx.conversation.blocks` registry; the bar renders the same disabled textarea it already renders without a workspace, with the blocker's own localized reason as the placeholder — except the model seat, which a block deliberately leaves live, because choosing a model is how the user clears it. The push direction is forced — ui-model already depends on ui-conversation, so ui-conversation cannot read it back.
+
+The gate is `routable`, NOT "the current target matches no advertised group". Catalog membership is advisory by design: a route serving a model it stopped advertising is absent from the groups yet perfectly usable, and blocking there would break a supported configuration (a narrowed `models` list over a live route). `routable` is also three-valued on the client — `null` before the first load or after a failed one never blocks, so a slow or unreachable Host cannot lock a working composer.
+
+## Alternatives considered
+
+- **Falling back to the composition entry when the stored route is unregistered.** Rejected: the composer would then name the shipped DeepSeek model instead of prompting, which is both a silent switch to a provider the user did not pick and the opposite of the requested behavior.
+- **Validating and clearing a stale default.** Rejected: catalog membership is advisory by design (`buildModelCatalog` documents it), so an adapter may serve a model its own catalog stopped advertising; self-healing would break that deliberate case.
+- **A `settings.update` merge patch.** Rejected: it cannot clear `reasoningEffort`, so a switch from a reasoning model to a plain one leaves an effort the next session fails on.
+- **Persisting only from blank sessions.** Rejected: the most informative switch is the one made mid-conversation after seeing a model underperform, and that one would never be saved.
+- **A separate "set as default" affordance.** Rejected for now: it adds a second gesture for what every comparable product infers from the switch itself. The cost is that a temporary switch in an old session also moves the default.

.agents/notes/implemented/feature/2026-08-07-default-model-follows-the-picker.zh.md

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+# Agent Note: 默认模型跟随选择器
+
+Status: implemented
+
+[English](2026-08-07-default-model-follows-the-picker.md) | 中文
+
+## 问题
+
+新会话的起始路由被冻结在网关的组合条目里（web-app bundle patch 中的 `api-gateway` 行）。在一段对话里切换模型只影响这段对话：下一个会话又回到出厂默认，而要改这个默认值，唯一的办法是手工编辑一条 `cordis.yml` 行并重启。组合层与每会话选择之间没有用户设置这一层。
+
+## 决定
+
+`ApiProxyService` 把自己的 `{provider, model, reasoningEffort?}` 切片注册为 `api-gateway` 设置段：组合条目是 `base` 层，`settings.yaml` 把用户的选择叠加其上。`workspaceRoot` 留在段外——它是启动器事实，不是偏好。`reasoningEffort` 则是镜像的一例：它在段里、但**不在**插件配置里，因为 seam 是按字段把用户层合并到组合条目之上的，缺席的键覆盖不了存在的键。组合层设的推理等级因此会在此后每一次切到不支持推理的模型时继续存活——正是整段 `replace` 想要杜绝的那种滞留。何况推理等级本就是按模型的事实，它的部署级默认值属于适配器 profile，那里是按模型解析的。
+
+`session.selectModel` 把被接受的切换记录为新的默认值。没有另一个单独的手势：在输入框切模型**就是**选定默认值的方式。写入用 `replace` 而非 `update`——切到一个不支持推理的模型必须清掉已存的等级，而合并补丁会把它滞留下来，让下一个会话在它上面失败。存储失败只记日志，不撤销这次切换（它对自己所在的会话已经生效）；没有设置提供方的部署保留组合条目，切换只停留在进程内。
+
+`ApiProxyDefaults` 改为携带 `defaultTarget()` 与 `persistDefaultTarget()` 两个闭包，而不是扁平的 `provider`／`model` 字段，这样 `createApiProxy` 不需要知道设置这条缝的存在。
+
+`targetFor` 在**每一次**读取时解析各级，而不是只在创建时种一次 ref：本进程内的显式选择，其次是该会话自己最新记录的 `request/header`，最后才是活的默认值。两个方向都依赖这次重新读取。已经跑过一轮的会话此后永远从自己的日志推导，改默认值不会重定向它；而仍然空白的会话会用上它创建之后才保存的默认值——这一点很关键，因为新建会话是复用空白会话而不是再开一个，创建时种下的值恰好会在这个功能存在的意义所在的流程里显示已被取代的模型。
+
+存下来的路由不做注册表校验。默认值指向一条模型页已经删除的路由时，它照样作为 `current` 送到 `session.models`，匹配不到任何已公布的分组——而这正是让输入框选择器已有的回退提示重新选择、而不是显示一个部署根本够不着的模型的原因。
+
+## 影响
+
+`ApiProxyDefaults` 形状变了，约 40 处测试构造点随之更新。`host.describe` 现在报告的是活的默认值而非捕获的快照，这本就是它一直想表达的含义。用户一旦切换模型，`settings.yaml` 就会多出一个 `api-gateway:` 段；`api-gateway` 这个 namespace 刻意**没有**加进网关的暴露名单，因此设置页既不读也不写它——模型选择器就是它的编辑器。
+
+## 后续：让发不出消息的会话禁止输入
+
+默认值指向一条模型页已删除的路由时，编辑器显示「选择模型」，输入框却仍接受消息，然后这一轮在适配器内部失败。两处改动关掉这个口子。
+
+宿主拒绝。`session.prompt` 检查是否有适配器服务该会话的路由，在开启轮次之前就以 `model-unavailable` 应答。这是执行边界：客户端禁用编辑器只是提示性设计，这个方法始终可被调用。
+
+编辑器变惰性。`session.models` 报告 `routable`，ui-model 经新的 `ctx.conversation.blocks` 注册表推送一个 block；输入栏渲染的仍是它在没有 Workspace 时就会渲染的那个禁用 textarea，只是把抬起方自己的本地化理由作为 placeholder——唯独模型 seat 被 block 刻意保留可用，因为用户正是靠选模型来解除它。推送方向是被迫的——ui-model 本就依赖 ui-conversation，因此 ui-conversation 读不回去。
+
+闸门是 `routable`，**不是**「当前目标匹配不到任何已公布分组」。目录成员关系按设计是咨询性的：一条仍在服务、只是不再公布该模型的路由不在分组里，却完全可用，在那里阻断会破坏一种受支持的配置（对一条活着的路由收窄 `models` 列表）。`routable` 在客户端还是三值的——首次加载之前或加载失败之后的 `null` 绝不阻断，因此慢的或够不着的宿主锁不死一个本来能用的编辑器。
+
+## 考虑过的替代方案
+
+- **存下来的路由未注册时回落到组合条目。** 否决：那样输入框会显示出厂的 DeepSeek 模型而不是提示选择，既是静默切到用户没选的提供方，也与要求的行为正好相反。
+- **校验并清空失效的默认值。** 否决：目录成员关系按设计是咨询性的（`buildModelCatalog` 有注释说明），适配器可以服务一个自己目录已不再公布的模型；自动修复会破坏这个刻意保留的情形。
+- **用 `settings.update` 合并补丁。** 否决：它清不掉 `reasoningEffort`，于是从推理模型切到普通模型会留下一个等级，让下一个会话在它上面失败。
+- **只在空白会话里持久化。** 否决：最有信息量的切换恰恰是对话到一半发现模型不行时做的那一次，而它永远存不下来。
+- **单独做一个「设为默认」的入口。** 目前否决：同类产品都从切换本身推断的事情，它却要多一个手势。代价是在老会话里的临时切换也会移动默认值。