docs(client): document trajectory conversation assembly

.agents/notes/implemented/architecture/2026-08-09-client-conversation-node-assembly.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/architecture/2026-08-09-client-conversation-node-assembly.md
-2026-08-09-client-conversation-node-assembly.md: 16a39539064644e5467f701789a7e2ef1f7ff172
-2026-08-09-client-conversation-node-assembly.zh.md: 0e0fbdf8f3320393022528e6e3fe2cf0d492a1d3
+2026-08-09-client-conversation-node-assembly.md: 1d5fd20bfa8c3b370f736937d54a668ca7f19ca3
+2026-08-09-client-conversation-node-assembly.zh.md: 6f0acc448950cdedcb249ada8cfd931a21765b3e

.agents/notes/implemented/architecture/2026-08-09-client-conversation-node-assembly.md

@@ -148,7 +148,7 @@ The Assembler verifies `node.key === context.key` and `node.target === target`.
 
 `current` lets a Definition distinguish "never materialized" from "already materialized and now hidden." Assistant retry and Turn Error suppression use it to avoid illegal Node withdrawal.
 
-A Definition may branch by target to construct different data, while matching, Context identity, and State remain target-neutral. This change registers only the `chat` builder; Trajectory remains on its independent `session-history` fold until it gains a registered target.
+A Definition owns at most one view target; state-only Definitions omit both `target` and `buildViewNode()`. Chat and Trajectory register separate business Definitions even when they recognize the same durable Event family, while the shared Assembler supplies the same matching, replay, Location, and publication mechanics to both targets.
 
 #### No generic `end()`
 
@@ -328,7 +328,7 @@ When business logic deliberately changes a materialized Node to hidden, it leave
 
 The concrete Tool renderer remains governed by the [`ui-tool ownership decision`](2026-08-08-client-tool-presentation-ownership.md). Tool Definition supplies recursive root/subcall data, and `ui-tool` dispatches concrete presentation by the Tool-name keyed slot.
 
-Trajectory has no registered target and does not consume the Chat Builder's legacy slice. Its activated `SessionHistoryInspection` keeps an independent history fold, while the ordinary Session snapshot no longer runs a second transcript fold. The Chat Builder retains its legacy slice for StatsLine and the top-level public compatibility fields; a future Trajectory migration does not change the Event Definition, Context, Reader, or Location contracts.
+Trajectory registers its own target and business Definitions against the same Assembler and Session event window as Chat. Its target builder preserves the stage-oriented read model without consuming the Chat Builder's legacy slice or running an independent history fold. The Chat Builder retains its legacy slice for StatsLine and the top-level public compatibility fields; target-specific Definitions do not change the shared Context, Reader, or Location contracts.
 
 ## Runtime and render path
 
@@ -339,20 +339,17 @@ Session Event window
        -> Context matches + State + Location
        -> Definition.buildLocationData(step -> turn)
             -> StepLocation.data / TurnLocation.data
-       -> Definition.buildViewNode(target = chat)
-  -> ChatSnapshotBuilder
-       -> order[] + keyed Node store + Location index + timeline
-  -> ChatView
-       -> ChatNodeSeat(key)
-       -> conversation.chat.node(entryKey = node.kind, hookContext = key)
-            -> slot-level useTurnData(businessKey)
+       -> Definition.buildViewNode() for its declared target
+  -> target View Builder
+       -> chat: ChatSnapshotBuilder -> ChatView -> keyed ChatNodeSeat
+       -> trajectory: TrajectorySnapshotBuilder -> stages/layout/table
 ```
 
 ## Verification
 
 Runtime tests pin Definition lifecycle registration, exact-ID append, update-before-start collection followed by forward replay after start, prepend identity, Reader window-gap repair, transitive dependencies, Location closure, Step→Turn data phase order, Location data replacement, publication cadence, illegal withdrawal, and per-target Builders.
 
-Conversation tests cover every built-in Definition, Assistant Step data, Turn Tail and Deliverables Turn data, Chat ordering and structural sharing, selector isolation, Assistant and Tool running-to-settled identity, nested Code Dispatch, steering, Compaction, Retry, interruption, load-older anchoring, and slot dispatch.
+Conversation tests cover every built-in Chat Definition, Assistant Step data, Turn Tail and Deliverables Turn data, Chat ordering and structural sharing, selector isolation, Assistant and Tool running-to-settled identity, nested Code Dispatch, steering, Compaction, Retry, interruption, load-older anchoring, and slot dispatch. Trajectory tests cover its independently registered Message, Assistant, Tool, Compaction, Request-header, and boundary Definitions together with the preserved stage-oriented view model.
 
 Slot type/runtime tests pin required parent-provided common inject, the `hookContext` type, Hook isolation across Node contexts, stable factory/Hook identity, and the absence of business-renderer rerenders for unrelated Session publications. Existing entry-owned Observable Hook tests continue to pin the path that does not use a contextual factory.
 
@@ -382,7 +379,7 @@ History-path tests cover complete replace, non-overlapping prepend, overlapping-
 
 **Add generic `end()`, prepared, or window-reset lifecycles.** Rejected: businesses have different completion conditions, and a pagination gap is not a business lifecycle. Business Events update State, Location close triggers replay/build, and Reader dependencies own pagination invalidation.
 
-**Register separate Event Definitions for Chat and Trajectory.** Rejected: identity, State, and Location are target-neutral. `buildViewNode(target)` and each Builder express view differences; Trajectory's independent history fold remains until it registers its own Builder.
+**Reuse one Event Definition across Chat and Trajectory by branching in `buildViewNode(target)`.** Rejected: the views require different business State and intermediate records, so a shared Definition would make each package carry the other's conditions and payloads. Separate target-owned Definitions keep those choices local while sharing the Assembler's ingestion and lifecycle contracts.
 
 **Add a generic layout model above final business Nodes.** Rejected: activity, tail candidacy, and layout enums would centralize current Chat business semantics in the engine again. Final Nodes carry renderer-required data directly and share only identity, ordering, and Location facts.
 
@@ -406,4 +403,4 @@ Steps and Turns become stable homes for cross-business aggregates. Turn Tail and
 
 The cost is new Runtime contracts for Registry, Assembler, Location data, dependency replay, and per-target Builders, plus parent-owned common inject and per-occurrence `hookContext` in UI Slots. Definition authors must understand stable IDs, unique starts, forward replay, Step→Turn publication order, read-only Reader access, and the prohibition on Node withdrawal.
 
-`useTurnData()` does not revoke the standard `useSession` capability from session-scoped renderers, so this boundary relies on API guidance and tests rather than capability isolation. Registry changes remain low-frequency full rebuilds; the Chat Builder still maintains a legacy slice for StatsLine and the top-level public fields, Trajectory still owns an independent history fold, and built-in Definitions currently remain centralized in `ui-conversation`. These compatibility boundaries do not return business interpretation to Session.
+`useTurnData()` does not revoke the standard `useSession` capability from session-scoped renderers, so this boundary relies on API guidance and tests rather than capability isolation. Registry changes remain low-frequency full rebuilds; the Chat Builder still maintains a legacy slice for StatsLine and the top-level public fields, while Trajectory owns target-specific Definitions and a Builder over the shared Session window. Built-in Definitions remain in their respective UI packages, and these compatibility boundaries do not return business interpretation to Session.

.agents/notes/implemented/architecture/2026-08-09-client-conversation-node-assembly.zh.md

@@ -148,7 +148,7 @@ Assembler 校验 Node `key === context.key` 且 Node `target === target`。业
 
 `current` 让 Definition 区分“从未生成”与“已经生成后需要隐藏”。Assistant retry 和 Turn Error suppression 使用它避免非法的 Node 撤回。
 
-Definition 可以针对 target 分支构造不同 data，但匹配、Context identity 和 State 保持 target-neutral。本次只注册 `chat` builder；在拥有注册 target 之前，Trajectory 继续使用独立的 `session-history` fold。
+一个 Definition 最多拥有一个 view target；仅维护状态的 Definition 同时省略 `target` 与 `buildViewNode()`。即使 Chat 与 Trajectory 识别同一持久 Event 族，它们也分别注册自己的业务 Definition；共享 Assembler 则为两个 target 提供相同的匹配、replay、Location 与发布机制。
 
 #### 不提供通用 `end()`
 
@@ -328,7 +328,7 @@ Assistant streaming 到 final、Tool running 到 settled 只更新同一个 Seat
 
 具体 Tool renderer 仍由 [`ui-tool ownership decision`](2026-08-08-client-tool-presentation-ownership.md) 约束。Tool Definition 只交付递归 root/subcall data，`ui-tool` 再按 Tool name keyed slot 分发具体表现。
 
-Trajectory 尚未注册 target，也不消费 Chat Builder 的 legacy slice。它已激活的 `SessionHistoryInspection` 继续维护独立 history fold，而普通 Session snapshot 不再运行第二套 transcript fold。Chat Builder 为 StatsLine 和顶层公共兼容字段保留 legacy slice；未来迁移 Trajectory 不改变 Event Definition、Context、Reader 或 Location 契约。
+Trajectory 针对与 Chat 相同的 Assembler 和 Session 事件窗口注册自己的 target 与业务 Definition。它的 target builder 保留 stage-oriented read model，既不消费 Chat Builder 的 legacy slice，也不运行独立 history fold。Chat Builder 为 StatsLine 和顶层公共兼容字段保留 legacy slice；target 专属 Definition 不改变共享的 Context、Reader 或 Location 契约。
 
 ## Runtime and render path
 
@@ -339,20 +339,17 @@ Session Event window
        -> Context matches + State + Location
        -> Definition.buildLocationData(step -> turn)
             -> StepLocation.data / TurnLocation.data
-       -> Definition.buildViewNode(target = chat)
-  -> ChatSnapshotBuilder
-       -> order[] + keyed Node store + Location index + timeline
-  -> ChatView
-       -> ChatNodeSeat(key)
-       -> conversation.chat.node(entryKey = node.kind, hookContext = key)
-            -> slot-level useTurnData(businessKey)
+       -> Definition.buildViewNode() for its declared target
+  -> target View Builder
+       -> chat: ChatSnapshotBuilder -> ChatView -> keyed ChatNodeSeat
+       -> trajectory: TrajectorySnapshotBuilder -> stages/layout/table
 ```
 
 ## Verification
 
 Runtime tests 固定 Definition 生命周期注册、exact-ID append、update-before-start 收集与 start 后正序 replay、prepend identity、Reader window-gap 修复、传递依赖、Location closure、Step→Turn data phase order、Location data replacement、publication cadence、非法撤回和 per-target Builder。
 
-Conversation tests 覆盖全部内建 Definition、Assistant Step data、Turn Tail 与 Deliverables Turn data、Chat 排序和结构共享、selector isolation、Assistant/Tool running-to-settled identity、nested Code Dispatch、steering、Compaction、Retry、interruption、load-older anchoring 和 slot dispatch。
+Conversation tests 覆盖全部内建 Chat Definition、Assistant Step data、Turn Tail 与 Deliverables Turn data、Chat 排序和结构共享、selector isolation、Assistant/Tool running-to-settled identity、nested Code Dispatch、steering、Compaction、Retry、interruption、load-older anchoring 和 slot dispatch。Trajectory tests 则覆盖它独立注册的 Message、Assistant、Tool、Compaction、Request-header 与 boundary Definition，以及继续保留的 stage-oriented view model。
 
 Slot type/runtime tests 固定父注册必须提供声明的 common inject、`hookContext` 类型、不同 Node context 的 Hook 隔离、factory/Hook identity 稳定，以及无关 Session publication 不重渲染业务 renderer。原 entry-owned Observable Hook 测试继续固定未使用 contextual factory 的路径。
 
@@ -382,7 +379,7 @@ Assembled Web snapshot、GUI 和浏览器场景覆盖真实 plugin graph。浏
 
 **增加通用 `end()`、prepared 或 window reset 生命周期。** 拒绝：不同业务完成条件不同，分页缺口也不是业务生命周期。业务 Event 更新 State，Location close 触发 replay/build，Reader dependency 负责补页失效。
 
-**为 Chat 与 Trajectory 注册两套 Event Definition。** 拒绝：identity、State 和 Location 与 target 无关。视图差异由 `buildViewNode(target)` 和各自 Builder 表达；Trajectory 在注册自己的 Builder 之前继续使用独立 history fold。
+**在同一个 Event Definition 内通过 `buildViewNode(target)` 为 Chat 与 Trajectory 分支。** 拒绝：两种视图需要不同的业务 State 与中间记录，共用 Definition 会迫使每个 package 携带另一边的条件与 payload。target 自有的 Definition 把这些选择留在本地，同时复用 Assembler 的摄入与生命周期契约。
 
 **在最终业务 Node 上再叠一层通用 layout model。** 拒绝：activity、tail candidacy 和 layout enum 会把当前 Chat 的业务语义重新集中到引擎。最终 Node 直接携带 renderer 所需 data，只共享 identity、排序和 Location 事实。
 
@@ -406,4 +403,4 @@ Step/Turn 成为业务间共享聚合的稳定宿主。Turn Tail 和 Deliverable
 
 代价是 Runtime 新增 Registry、Assembler、Location data、依赖重放和 per-target Builder 契约，UI Slots 也新增 parent-owned common inject 与 per-occurrence `hookContext`。Definition 作者必须理解稳定 ID、唯一 start、正序 replay、Step→Turn 发布顺序、只读 Reader 和 Node 不撤回规则。
 
-`useTurnData()` 不撤销 session-scoped renderer 的标准 `useSession`，因此该边界依靠 API 引导和测试，而不是能力隔离。Registry 变化仍是低频完整 rebuild；Chat Builder 继续为 StatsLine 和顶层公共字段维护 legacy slice，Trajectory 继续拥有独立 history fold，内建 Definitions 暂时集中在 `ui-conversation`。这些是兼容边界，不把业务解释权交还给 Session。
+`useTurnData()` 不撤销 session-scoped renderer 的标准 `useSession`，因此该边界依靠 API 引导和测试，而不是能力隔离。Registry 变化仍是低频完整 rebuild；Chat Builder 继续为 StatsLine 和顶层公共字段维护 legacy slice，Trajectory 则在共享 Session 窗口上拥有 target 专属 Definition 与 Builder。内建 Definition 分别留在所属 UI package；这些兼容边界不把业务解释权交还给 Session。