docs(web): describe session title projection

.agents/notes/implemented/feature/2026-07-21-log-backed-session-titles.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
-2026-07-21-log-backed-session-titles.md: cd0d2a4bab9b6504c65e942c0e03bce79488364e
-2026-07-21-log-backed-session-titles.zh.md: b90ac6c59677e6542733210b91de38ef1169c760
+2026-07-21-log-backed-session-titles.md: 494187a73c58fb2313d802825c3ec9f9994d6f2b
+2026-07-21-log-backed-session-titles.zh.md: cae51cca920fad748cb1944d35cc1b80850eb6ee

.agents/notes/implemented/feature/2026-07-21-log-backed-session-titles.md

@@ -40,7 +40,7 @@ Automatic provider failures are nonfatal warnings and retain the latest title. E
 
 A fork inherits seed title events unchanged, like the rest of its source log. The first-message provider does not automatically retitle a fork. The all-messages provider may append a child-owned revision after a later child prompt, using inherited and new eligible messages.
 
-`ctx.sessionQuery.readTitle()` folds one live-preferred or persisted log without loading titles during `listSessions()`. ACP maps the event to `session_info_update` during both live streaming and load replay, using the event timestamp for `updatedAt`. The TUI uses the latest title as its header subtitle and sets the terminal window title to `<session title> — <configured product title>` after terminal-safe rendering. A synthetic title turn remains a completed durability boundary for the metadata write; consumers reporting agent completion use the core `findLastMessageTurnEnd()` fold so a later title, injection, or other plugin-owned turn cannot replace the preceding message-triggered outcome.
+`ctx.sessionQuery.readTitle()` folds one live-preferred or persisted log without loading titles during `listSessions()`. ACP maps the event to `session_info_update` during both live streaming and load replay, using the event timestamp for `updatedAt`. The TUI uses the latest title as its header subtitle and sets the terminal window title to `<session title> — <configured product title>` after terminal-safe rendering. The Web host folds the same log state into a validated mux control frame after each attached-session subscription baseline and immediately after forwarding a live raw title event. The browser retains only newer title event seqs even when the control frame precedes list or session-instance creation; sidebar labels, search, breadcrumbs, and the browser title then react to the projected revision. `session.list` remains metadata-only, so a cold persisted session uses the cwd basename or id until opening or resuming it attaches the log. The browser title uses `<session title> — <existing HTML title>` only for a selected titled session and otherwise preserves the product title. A synthetic title turn remains a completed durability boundary for the metadata write; consumers reporting agent completion use the core `findLastMessageTurnEnd()` fold so a later title, injection, or other plugin-owned turn cannot replace the preceding message-triggered outcome.
 
 ## Alternatives considered
 
@@ -54,6 +54,7 @@ A fork inherits seed title events unchanged, like the rest of its source log. Th
 ## Consequences
 
 - Titles survive JSONL and SQLite persistence, replay through ACP, and follow fork inheritance without a separate mutable record.
+- Web title delivery stays incremental and log-backed without a title index or persisted-list scan; cold list rows improve after attach.
 - A fallback appears without an auxiliary call; deployments choose whether better titles justify model cost and whether later prompts should retitle a session.
 - Auxiliary request records and late accepted titles consume event seqs and may create balanced zero-step turns, so persistence exposes both attempted dispatches and accepted updates even though model history and KV-cache identity do not change.
 - One provider and monotonic per-session revisions make disposal, supersession, and stale-result rejection explicit, at the cost of leaving multi-strategy precedence to a composite provider.

.agents/notes/implemented/feature/2026-07-21-log-backed-session-titles.zh.md

@@ -40,7 +40,7 @@ Status: implemented
 
 与源日志的其他部分相同，fork 会原样继承作为种子的标题事件。首消息提供方不会自动为 fork 重新生成标题。全部消息提供方可以在子会话出现后续提示词后追加一项归子会话所有的修订，并使用继承的合格消息和新增的合格消息。
 
-`ctx.sessionQuery.readTitle()` 会折叠一份实时优先或已持久化的日志，而不会在 `listSessions()` 期间加载标题。ACP（Agent Client Protocol）会在实时流式输出和加载回放期间把该事件映射到 `session_info_update`，并使用事件时间戳作为 `updatedAt`。TUI 使用最新标题作为其标题栏副标题，并在完成终端安全渲染后，将终端窗口标题设置为 `<session title> — <configured product title>`。合成标题轮次本身仍会完成，并作为元数据写入的持久性边界；报告 agent 完成情况的消费方使用核心的 `findLastMessageTurnEnd()` 折叠逻辑，因此后续的标题轮次、注入轮次或其他归插件所有的轮次无法取代此前由消息触发的结果。
+`ctx.sessionQuery.readTitle()` 会折叠一份实时优先或已持久化的日志，而不会在 `listSessions()` 期间加载标题。ACP（Agent Client Protocol）会在实时流式输出和加载回放期间把该事件映射到 `session_info_update`，并使用事件时间戳作为 `updatedAt`。TUI 使用最新标题作为其标题栏副标题，并在完成终端安全渲染后，将终端窗口标题设置为 `<session title> — <configured product title>`。Web host 会在每个已附加会话的订阅基线之后，以及转发实时原始标题事件后立即，将同一份日志状态折叠为经过校验的 mux 控制帧。即使控制帧先于列表或会话实例创建抵达，浏览器也只保留标题事件 seq 较新的版本；侧边栏标签、搜索、面包屑和浏览器标题会随投影后的修订更新。`session.list` 仍只包含元数据，因此尚未打开的持久化会话会继续以 cwd 基名或 id 作为回退，直至打开或恢复会话时附加其日志。浏览器仅在选中已有标题的会话时将标题设置为 `<session title> — <existing HTML title>`，否则保留产品标题。合成标题轮次本身仍会完成，并作为元数据写入的持久性边界；报告 agent 完成情况的消费方使用核心的 `findLastMessageTurnEnd()` 折叠逻辑，因此后续的标题轮次、注入轮次或其他归插件所有的轮次无法取代此前由消息触发的结果。
 
 ## 考虑过的替代方案
 
@@ -54,6 +54,7 @@ Status: implemented
 ## 后果
 
 - 标题可以在 JSONL 和 SQLite 持久化中存续，通过 ACP 回放，并遵循 fork 继承语义，而无需单独的可变记录。
+- Web 标题仍以增量方式从日志交付，无需标题索引或扫描持久化列表；冷启动列表项会在会话附加后改用标题。
 - 回退标题无需辅助调用即可出现；部署方可以自行决定更优标题是否值得模型成本，以及后续提示词是否需要重新生成会话标题。
 - 辅助请求记录和延迟接受的标题会占用事件 seq，并可能创建平衡的零步骤轮次，因此持久化会同时呈现尝试发起的调用与已接受的更新，尽管模型历史和 KV 缓存标识保持不变。
 - 单个提供方和每会话单调递增的修订号让释放、取代和陈旧结果拒绝行为明确可见，但多策略优先级必须由复合提供方负责。