feat(agent-workspace): add history drill-down

Author: Jacobinwwey

docs/diataxis/en/explanation/agent-conversation-focus-mode-plan.md

@@ -464,10 +464,11 @@ It is conversation-product hardening on top of the shipped shell.
 `M8.26` now adds capability-taxonomy summary cards and latest study-action feedback so the current atom reads like a result surface instead of only a button cluster.
 `M8.27` now adds recent current-atom result history so the rail preserves the last successful actions across turns instead of resetting to a blank continuity surface.
 `M8.28` now adds localized result-detail previews inside that recent-activity history so the rail preserves what those actions produced, not just that they happened.
+`M8.29` now adds expandable history drill-down so the rail can reveal event metadata without leaving the active-atom surface.
 
 Priority order:
 
-1. history drill-down and continuity-driven follow-up affordances on top of the shipped preview-enabled current-atom recent-activity card,
+1. continuity-driven follow-up affordances on top of the shipped drill-down-enabled current-atom recent-activity card,
 2. only then deeper personalization work,
 3. markdown-reader improvements only when they clearly compound the same study loop.
 

docs/diataxis/en/explanation/development-progress-dashboard.md

@@ -18,9 +18,9 @@ Current top priority is not feature-count expansion.
 Current top priority is **conversation-product hardening on top of the already-green backend baseline**:
 
 - keep backend sufficiency as a standing decision gate rather than an active execution lane,
-- keep closing the correction/product/operator gap exposed after `M8.20-M8.28`,
-- treat `M8.23` as the operator-visibility baseline for conversation-memory/correction actions, `M8.24` as the active-atom action-surface baseline, `M8.25` as the active-atom pane-state continuity baseline, `M8.26` as the active-atom study-loop summary baseline, `M8.27` as the active-atom recent-result continuity baseline, and `M8.28` as the active-atom result-preview baseline,
-- move the remaining near-term budget into history drill-down and continuity affordances instead of reopening backend scope,
+- keep closing the correction/product/operator gap exposed after `M8.20-M8.29`,
+- treat `M8.23` as the operator-visibility baseline for conversation-memory/correction actions, `M8.24` as the active-atom action-surface baseline, `M8.25` as the active-atom pane-state continuity baseline, `M8.26` as the active-atom study-loop summary baseline, `M8.27` as the active-atom recent-result continuity baseline, `M8.28` as the active-atom result-preview baseline, and `M8.29` as the active-atom history-drill-down baseline,
+- move the remaining near-term budget into continuity follow-up affordances instead of reopening backend scope,
 - keep remote `main` CI interpretation evidence-based: the latest fully completed `main` workflow set is green, and new pushes should be treated as pending until their workflow set finishes.
 
 ## Current Mainline Snapshot (2026-04-21 M8.18)
@@ -223,6 +223,23 @@ Execution anchor:
   - diagnostics snapshot coverage for stored preview payloads,
   - EN/ZH re-render coverage for localized preview text.
 
+## Latest Mainline Increment (2026-04-21 M8.29 Active-Atom History Drill-Down)
+
+- Upgraded the recent-activity card from a preview list into an inspectable history surface:
+  - each recent current-atom result now exposes a details toggle,
+  - drill-down reveals event timestamp, operation id, result surface id, and measured duration,
+  - the expanded event stays pinned through runtime re-renders such as language changes.
+- Kept the slice frontend-bounded:
+  - no backend route, API contract, or persistence model changed,
+  - drill-down state lives only inside the agent-workspace runtime and reuses the bounded diagnostics event ring.
+- Closed the next inspectability gap after `M8.28`:
+  - operators can now inspect how a recent action was executed without leaving the active-atom rail,
+  - localized rerenders keep both preview text and expanded drill-down labels consistent instead of collapsing the inspection context.
+- Expanded regression coverage for:
+  - recent-history details toggles on the active-atom rail,
+  - expanded metadata rendering for current-atom history entries,
+  - EN/ZH rerender continuity while a history entry remains expanded.
+
 ## Latest Mainline Increment (2026-04-14 M1 Baseline)
 
 - Added first `AgentConversationAPI` contract surface:
@@ -1326,8 +1343,8 @@ Note: foundation-lane gates now exist on `main`; keep them in the normal verific
 
 1. Treat backend sufficiency as closed-by-default while the gate remains green; do not reopen heavier backend work without new measured pressure.
 2. Treat remote `main` CI as evidence-bound to the latest fully completed workflow set; only reopen CI-triage narrative when a fresh failing run exists.
-3. Make the next planning round about post-`M8.28` bounded conversation-product hardening:
-   - history drill-down and continuity-driven follow-up affordances on top of the shipped preview-enabled current-atom recent-activity card before deeper personalization work,
+3. Make the next planning round about post-`M8.29` bounded conversation-product hardening:
+   - continuity-driven follow-up affordances on top of the shipped drill-down-enabled current-atom recent-activity card before deeper personalization work,
    - only then deeper personalization work,
    - markdown-reader improvements only when they compound the same study loop.
 4. Treat notification-threshold governance as closed after `M7.29`; do not plan `M7.30+` unless a materially new operator requirement appears.

docs/diataxis/en/explanation/local-backend-sufficiency-and-escalation-plan.md

@@ -247,8 +247,8 @@ Recommended next product order:
    - extend explicit conversation memory APIs beyond the current snapshot/read/managed-key inspection and note/correction/eviction surface,
    - the minimum correction / feedback closure is now integrated through explicit next-step guidance on missing managed state,
    - operator-facing visibility for conversation-memory and correction actions is now integrated through persisted diagnostics summary/index counts,
-   - stronger agent action surfaces around focus mode and learning path are now integrated through the active-atom quick-action rail, toolbar routing, continuity notes/path-target diagnostics, capability-taxonomy summary cards, the recent-activity history card, and localized result-detail previews on that history surface,
-   - next prioritize history drill-down and continuity-driven follow-up affordances on top of the shipped preview-enabled current-atom recent-activity card before deeper personalization work.
+   - stronger agent action surfaces around focus mode and learning path are now integrated through the active-atom quick-action rail, toolbar routing, continuity notes/path-target diagnostics, capability-taxonomy summary cards, the recent-activity history card, localized result-detail previews on that history surface, and expandable history drill-down,
+   - next prioritize continuity-driven follow-up affordances on top of the shipped drill-down-enabled current-atom recent-activity card before deeper personalization work.
 2. markdown-reader improvement:
    - only when it clearly compounds knowledge review or focus-mode study loops.
 

docs/diataxis/zh/explanation/agent-conversation-focus-mode-plan.md

@@ -452,10 +452,11 @@
 `M8.26` 现在又补上 capability-taxonomy summary card 与最近 study-action 反馈，让当前 atom 更像结果面，而不只是动作按钮堆叠。
 `M8.27` 现在又补上当前 atom recent result history，让 rail 在跨轮次时保留最近成功动作，而不是重新退回空白 continuity surface。
 `M8.28` 现在又在这条 recent-activity history 里补上本地化 result-detail preview，让 rail 保留的不只是“发生过什么动作”，还包括“动作产出了什么”。
+`M8.29` 现在又补上可展开的 history drill-down，让 rail 不离开当前 atom surface 也能检查事件元数据。
 
 优先顺序：
 
-1. 围绕已落地且带 preview 的 current-atom recent-activity card 继续补 history drill-down 与 continuity-driven follow-up affordance，
+1. 围绕已落地且支持 drill-down 的 current-atom recent-activity card 继续补 continuity-driven follow-up affordance，
 2. 之后才进入更深的 personalization 工作，
 3. Markdown 阅读器提升只有在能明确复利同一学习闭环时才进入前列。
 

docs/diataxis/zh/explanation/development-progress-dashboard.md

@@ -18,9 +18,9 @@
 当前重心是 **建立在已转绿 backend 基线之上的 conversation-product 加固**：
 
 - 让 backend sufficiency 继续作为常驻 decision gate，而不是继续占用主动执行预算，
-- 持续收口 `M8.20-M8.28` 之后暴露出的 correction / product / operator 缺口，
-- 将 `M8.23` 视作 conversation-memory / correction action 的 operator-visibility 基线，将 `M8.24` 视作当前 atom action-surface 基线，将 `M8.25` 视作当前 atom pane-state continuity 基线，将 `M8.26` 视作当前 atom study-loop summary 基线，将 `M8.27` 视作当前 atom recent-result continuity 基线，并将 `M8.28` 视作当前 atom result-preview 基线，
-- 把剩余近端预算转向 history drill-down 与 continuity affordance，而不是重开 backend 范围，
+- 持续收口 `M8.20-M8.29` 之后暴露出的 correction / product / operator 缺口，
+- 将 `M8.23` 视作 conversation-memory / correction action 的 operator-visibility 基线，将 `M8.24` 视作当前 atom action-surface 基线，将 `M8.25` 视作当前 atom pane-state continuity 基线，将 `M8.26` 视作当前 atom study-loop summary 基线，将 `M8.27` 视作当前 atom recent-result continuity 基线，将 `M8.28` 视作当前 atom result-preview 基线，并将 `M8.29` 视作当前 atom history-drill-down 基线，
+- 把剩余近端预算转向 continuity follow-up affordance，而不是重开 backend 范围，
 - 远端 `main` CI 解释继续基于代码事实：最近一组已完整结束的主线工作流为绿色，新推送在整组工作流结束前只应视为 pending。
 
 ## 当前主线快照（2026-04-21 M8.18）
@@ -223,6 +223,23 @@
   - diagnostics snapshot 中 preview payload 的可见性，
   - EN/ZH 对 preview 文本的重渲覆盖。
 
+## 主线最新增量（2026-04-21 M8.29 当前 Atom History Drill-Down）
+
+- 已把 recent-activity card 从 preview 列表继续升级为可检查的 history surface：
+  - 每条当前 atom recent result 现在都带有 details toggle，
+  - drill-down 会暴露事件时间、operation id、result surface id，以及测得的 duration，
+  - 运行时重渲（例如语言切换）后，展开中的 history item 仍会保持展开。
+- 范围继续保持在前端层：
+  - 没有新增 backend route、API contract 或持久化模型，
+  - drill-down state 只存在于 agent-workspace runtime，并继续复用有界 diagnostics event ring。
+- 已收口 `M8.28` 之后的下一个可检查性缺口：
+  - 用户现在无需离开 active-atom rail，也能检查最近动作是如何执行的，
+  - 语言切换时，preview 与 drill-down 标签都会保持一致，不会丢失当前检查上下文。
+- 回归覆盖同步扩展到：
+  - active-atom rail 上 recent-history details toggle，
+  - 当前 atom history entry 的展开元数据渲染，
+  - history entry 展开状态下的 EN/ZH 重渲 continuity。
+
 ## 主线最新增量（2026-04-14 M1 基线）
 
 - 已新增第一版 `AgentConversationAPI` 合同面：
@@ -1329,8 +1346,8 @@ npm test -- src/learning/KnowledgeLearningPlatform.persistence.test.ts --runInBa
 
 1. backend sufficiency 在 gate 继续为绿时默认视为已收口；没有新的 measured pressure 前，不重开更重 backend 工作。
 2. 远端 `main` CI 继续以最近一组已完整结束的工作流为事实依据；只有出现新的失败 run，才重开 CI-triage 叙事。
-3. 下一轮 planning 应只讨论 post-`M8.28` 的有界 conversation-product 加固：
-   - 围绕已落地且带 preview 的 current-atom recent-activity card 继续补 history drill-down 与 continuity-driven follow-up affordance，再进入更深 personalization，
+3. 下一轮 planning 应只讨论 post-`M8.29` 的有界 conversation-product 加固：
+   - 围绕已落地且支持 drill-down 的 current-atom recent-activity card 继续补 continuity-driven follow-up affordance，再进入更深 personalization，
    - 之后才进入更深的 personalization 工作，
    - Markdown 阅读器提升只有在能复利同一学习闭环时才进入前列。
 4. notification-threshold 治理链路继续视为在 `M7.29` 后已收口；没有新的强运维需求前，不再规划 `M7.30+`。

docs/diataxis/zh/explanation/local-backend-sufficiency-and-escalation-plan.md

@@ -246,8 +246,8 @@
    - 在当前 snapshot/read/托管 key 检查与 note/correction/eviction 能力之上继续扩展显式 conversation memory API，
    - 最小 correction / feedback 收口已经通过“缺失托管状态 -> 显式下一步提示”集成到主线，
    - conversation-memory / correction action 的 operator-facing visibility 已经通过持久化 diagnostics summary / index 计数集成到主线，
-   - 围绕 focus mode 与 learning path 的更强 agent action surface 已经通过当前 atom quick-action rail、toolbar routing、continuity note / path-target diagnostics、capability-taxonomy summary card、recent-activity history card，以及这张卡上的本地化 result-detail preview 集成到主线，
-   - 下一步是在更深 personalization 之前，优先围绕已落地且带 preview 的 current-atom recent-activity card 继续补 history drill-down 与 continuity-driven follow-up affordance。
+   - 围绕 focus mode 与 learning path 的更强 agent action surface 已经通过当前 atom quick-action rail、toolbar routing、continuity note / path-target diagnostics、capability-taxonomy summary card、recent-activity history card、这张卡上的本地化 result-detail preview，以及可展开的 history drill-down 集成到主线，
+   - 下一步是在更深 personalization 之前，优先围绕已落地且支持 drill-down 的 current-atom recent-activity card 继续补 continuity-driven follow-up affordance。
 2. markdown reader 提升：
    - 只有在它能明确加强知识 review 或 focus-mode 学习闭环时，再提升优先级。