diff --git a/CHANGELOG.md b/CHANGELOG.md
index 12a9c01..76fd810 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,13 @@
 
 ## [Unreleased]
 
+### Added
+
+- PR 详情「评论」标签页演进为「活动」时间线（GitHub / Bitbucket）：把评论、提交更新、reviewer 评审决断（approve / needs-work / unapprove / dismiss）按时间倒序归并为一条活动时间线，保留原有评论内容、排序与编辑 / 回复 / 删除 / 内联代码能力。新增统一的 `listPullRequestActivity` 平台契约——GitHub 取自 `/pulls/{n}/reviews`、Bitbucket 取自 `/activities`（带时间戳的决断事件）。提交另保留独立「提交」标签页。
+  - 视觉：各条目统一为「图标节点 + 头像 + 加粗作者名 + 动词 + 时间」，一条竖向虚线轨贯穿图标列连接相邻条目；评论标题统一为「xxx 评论」并前置评论图标，正文整体缩进成挂在轨上的卡片；作者头像 / 文本与评论主体人一致，不做差异化。评审决断动词统一为「批准 / 要求修改」并用带色 chip（绿 / 琥珀 / 中性）突出。时间标签 hover 显示精确到秒的实际时间点。
+  - 新建评论：标签栏右侧「评论」按钮可直接发一条不锚到文件的 summary 评论，编辑框作为时间线首个节点（头像在轨上、编辑框缩进）展开，发布后新评论即时出现在顶部（新增 `publishSummaryComment` 平台契约 + `comments:create` 通道）。
+  - GitLab 走差异化设计：无统一活动事件源（CE 无审批、审批系统 note 解析脆弱），标签页保持纯「评论」视图（`capabilities.activityTimeline=false`），不混入提交 / 决断。
+
 ### Changed
 
 - **前端代码结构重构（可维护性）**：纯结构调整，对外接口与界面 / 交互行为均不变。重点：
@@ -16,6 +23,7 @@
 
 ### Fixed
 
+- PR 头部与详情页的评审状态 chip（pending / approved / needs_work、reviewer 的 approved / needs work / pending）此前为写死英文，现按界面语言出国际化文案（新增 `prStatus` 文案集，四语言）。
 - 切换不同 PR 时 diff 文件树「左栏空白 → 文件树整体弹出」的抖动：DiffView 改为 stale-while-loading——引入 `loadedPrId` 标记当前已渲染内容所属 PR，切 PR 期间保留旧树 / 旧内容渲染、上盖加载遮罩（延迟 150ms，命中缓存的快切换直接换新），并门控 content / comments / blame 拉取（避免「新 localId + 旧选中文件」错拉），新文件列表 ready 后整体替换。
 - diff 文件树首次加载时文件名被图标渲染推移的抖动：图标改用固定 16px 占位槽包裹，iconify 的 svg 晚一帧进 DOM 也不塌缩，文件名位置稳定。
 - 切换不同 PR 时评论页先闪「加载评论中」再渲新内容的空窗：改为 stale-while-loading——切 PR 期间保留旧评论渲染、上盖加载遮罩，新数据 ready 后整体替换；遮罩延迟 150ms 显示，命中本地缓存的快切换直接换新、零闪。
diff --git a/apps/desktop/src/main/controllers/pr.ts b/apps/desktop/src/main/controllers/pr.ts
index 66d946d..dd47fb8 100644
--- a/apps/desktop/src/main/controllers/pr.ts
+++ b/apps/desktop/src/main/controllers/pr.ts
@@ -37,6 +37,22 @@ export const replyComment: IpcController<'comments:reply'> = async (_event, req)
   return reply;
 };
 
+/**
+ * 在 PR 上新建一条 summary（顶层、不锚文件）评论，成功后清评论缓存 + 广播 comments:changed 让 UI 重拉。
+ */
+export const createComment: IpcController<'comments:create'> = async (_event, req) => {
+  const ctx = getContext();
+  const pr = await ctx.pr.findPrOrThrow(req.localId);
+  const adapter = ctx.pr.adapterForOrThrow(pr);
+  const created = await adapter.publishSummaryComment(
+    { projectKey: pr.repo.projectKey, repoSlug: pr.repo.repoSlug },
+    pr.remoteId,
+    req.body,
+  );
+  await ctx.pr.invalidateCommentsCache(pr.localId);
+  return created;
+};
+
 /**
  * 删除自己作者的远端评论（带 version 乐观锁）。失败原文抛给 renderer；成功后清缓存 + 广播。
  */
@@ -242,6 +258,20 @@ export const listCommits: IpcController<'diff:listCommits'> = async (_event, req
   );
 };
 
+/**
+ * 拉评审决断活动事件（approve / needs-work / unapprove / dismiss）。不缓存，量小；
+ * 进活动时间线时与评论 / 提交归并。平台取不到历史决断时 adapter 返回 []。
+ */
+export const listActivity: IpcController<'diff:listActivity'> = async (_event, req) => {
+  const ctx = getContext();
+  const pr = await ctx.pr.findPrOrThrow(req.localId);
+  const adapter = ctx.pr.adapterForOrThrow(pr);
+  return adapter.listPullRequestActivity(
+    { projectKey: pr.repo.projectKey, repoSlug: pr.repo.repoSlug },
+    pr.remoteId,
+  );
+};
+
 /**
  * 本地 git 算 PR 引入提交数（base=targetRef.sha 排除合入的目标提交）；镜像未齐返回 null。
  */
diff --git a/apps/desktop/src/main/ipc.ts b/apps/desktop/src/main/ipc.ts
index 7651c76..b7e4b51 100644
--- a/apps/desktop/src/main/ipc.ts
+++ b/apps/desktop/src/main/ipc.ts
@@ -58,6 +58,7 @@ export function registerIpcHandlers(deps: RegisterDeps): {
    * 评论 / 列表 / 状态 / 合并 / 镜像 / diff / 草稿 / pr-agent run 队列
    */
   ipcMain.handle('comments:reply', pr.replyComment); // 回复评论
+  ipcMain.handle('comments:create', pr.createComment); // 新建 summary 评论
   ipcMain.handle('comments:delete', pr.deleteComment); // 删除自己的评论
   ipcMain.handle('comments:edit', pr.editComment); // 编辑自己的评论
   ipcMain.handle('comments:fetchAttachment', pr.fetchAttachment); // 拉评论内嵌图片（代理带 PAT）
@@ -72,6 +73,7 @@ export function registerIpcHandlers(deps: RegisterDeps): {
   ipcMain.handle('diff:commentCountCached', pr.getCommentCountCached); // 评论数角标（仅缓存）
   ipcMain.handle('diff:listComments', pr.listComments); // 拉评论（缓存 + in-flight 去重）
   ipcMain.handle('diff:listCommits', pr.listCommits); // 提交列表
+  ipcMain.handle('diff:listActivity', pr.listActivity); // 评审决断活动事件（时间线）
   ipcMain.handle('diff:commitCount', pr.getCommitCount); // 提交数角标（本地 git）
   ipcMain.handle('diff:getBlame', pr.getBlame); // blame + PR 引入行
   ipcMain.handle('repo:getTotalSize', pr.getTotalSize); // 本地镜像总占用（设置页）
diff --git a/apps/desktop/src/renderer/src/components/common/icons.tsx b/apps/desktop/src/renderer/src/components/common/icons.tsx
index d3c36e7..44e2acd 100644
--- a/apps/desktop/src/renderer/src/components/common/icons.tsx
+++ b/apps/desktop/src/renderer/src/components/common/icons.tsx
@@ -408,6 +408,27 @@ export function NeedsWorkIcon({ size = 14 }: IconProps) {
   );
 }
 
+/** git commit 字形：横线上一个实心节点（活动时间线提交事件用）。 */
+export function CommitIcon({ size = 14 }: IconProps) {
+  return (
+    <svg
+      width={size}
+      height={size}
+      viewBox="0 0 16 16"
+      fill="none"
+      stroke="currentColor"
+      strokeWidth="1.6"
+      strokeLinecap="round"
+      strokeLinejoin="round"
+      aria-hidden="true"
+    >
+      <line x1="1.5" y1="8" x2="5" y2="8" />
+      <line x1="11" y1="8" x2="14.5" y2="8" />
+      <circle cx="8" cy="8" r="2.8" />
+    </svg>
+  );
+}
+
 /** 机器人头像：AutoPilot 启用态。天线 + 头框 + 双眼 + 两侧耳。 */
 export function RobotIcon({ size = 14 }: IconProps) {
   return (
diff --git a/apps/desktop/src/renderer/src/components/features/pr/PrHeader.tsx b/apps/desktop/src/renderer/src/components/features/pr/PrHeader.tsx
index 19e16e6..2689eab 100644
--- a/apps/desktop/src/renderer/src/components/features/pr/PrHeader.tsx
+++ b/apps/desktop/src/renderer/src/components/features/pr/PrHeader.tsx
@@ -60,7 +60,9 @@ export function PrHeader({
           · {pr.sourceRef.displayId} → {pr.targetRef.displayId}
         </span>
         <span> · </span>
-        <span className={`status-tag status-${pr.localStatus}`}>{pr.localStatus}</span>
+        <span className={`status-tag status-${pr.localStatus}`}>
+          {t(`prStatus.${pr.localStatus === 'needs_work' ? 'needsWork' : pr.localStatus}`)}
+        </span>
       </div>
       <div className="pr-header-actions">
         <a
diff --git a/apps/desktop/src/renderer/src/components/features/pr/PrPanel.tsx b/apps/desktop/src/renderer/src/components/features/pr/PrPanel.tsx
index f0807e6..b60ff46 100644
--- a/apps/desktop/src/renderer/src/components/features/pr/PrPanel.tsx
+++ b/apps/desktop/src/renderer/src/components/features/pr/PrPanel.tsx
@@ -4,7 +4,7 @@ import type { LocalPrStatus, PlatformCapabilities, StoredPullRequest } from '@me
 import { invoke } from '../../../api';
 import { useDraftsForPr } from '../../../stores/drafts-store';
 import { PaneLoading } from '../../common/Loading';
-import { CommentsPanel } from './tabs/comments/CommentsPanel';
+import { ActivityPanel } from './tabs/activity/ActivityPanel';
 import { CommitsPanel } from './tabs/CommitsPanel';
 // Monaco 编辑器（~10MB）懒加载：只有真正切到 Diff tab 才拉取 DiffView chunk，
 // 不阻塞窗口首帧 / PR 列表 / 首启向导。
@@ -53,6 +53,8 @@ export function PrPanel({
 }: PrPanelProps) {
   const { t } = useTranslation();
   const [tab, setTab] = useState<PrTab>('diff');
+  // 活动标签页「新建评论」编辑框开关（由标签栏「评论」按钮触发，编辑框出现在时间线顶部）
+  const [composingComment, setComposingComment] = useState(false);
   // 收到跳转请求 → 强制切到 Diff tab，DiffView 自己负责消费 anchor
   useEffect(() => {
     if (pendingDiffNav) setTab('diff');
@@ -146,6 +148,8 @@ export function PrPanel({
         commitCount={commitCount}
         totalDraftCount={totalDraftCount}
         publishableCount={publishableCount}
+        activityTimeline={capabilities?.activityTimeline ?? false}
+        onNewComment={() => setComposingComment(true)}
         showWhitespace={showWhitespace}
         onToggleWhitespace={() => setShowWhitespace((b) => !b)}
         showBlame={showBlame}
@@ -169,11 +173,14 @@ export function PrPanel({
             />
           </Suspense>
         </KeepAliveTab>
-        <KeepAliveTab active={tab === 'comments'}>
-          <CommentsPanel
+        <KeepAliveTab active={tab === 'activity'}>
+          <ActivityPanel
             pr={pr}
             onCommentsLoaded={(n) => setCommentCount(n)}
             capabilities={capabilities}
+            composing={composingComment}
+            onComposeClose={() => setComposingComment(false)}
+            currentUserName={currentUserName}
           />
         </KeepAliveTab>
         <KeepAliveTab active={tab === 'drafts'}>
diff --git a/apps/desktop/src/renderer/src/components/features/pr/tabs/PrInfoView.tsx b/apps/desktop/src/renderer/src/components/features/pr/tabs/PrInfoView.tsx
index 3cbcb30..f169bf4 100644
--- a/apps/desktop/src/renderer/src/components/features/pr/tabs/PrInfoView.tsx
+++ b/apps/desktop/src/renderer/src/components/features/pr/tabs/PrInfoView.tsx
@@ -1,4 +1,5 @@
 import { useMemo } from 'react';
+import { useTranslation } from 'react-i18next';
 import ReactMarkdown from 'react-markdown';
 import remarkGfm from 'remark-gfm';
 import type { ReviewerStatus, StoredPullRequest } from '@meebox/shared';
@@ -11,9 +12,11 @@ interface PrInfoViewProps {
 }
 
 function ReviewerStatusTag({ status }: { status: ReviewerStatus }) {
-  if (status === 'approved') return <span className="tag-approved">✓ approved</span>;
-  if (status === 'needsWork') return <span className="tag-needs-work">✗ needs work</span>;
-  return <span className="muted">pending</span>;
+  const { t } = useTranslation();
+  if (status === 'approved') return <span className="tag-approved">✓ {t('prStatus.approved')}</span>;
+  if (status === 'needsWork')
+    return <span className="tag-needs-work">✗ {t('prStatus.needsWork')}</span>;
+  return <span className="muted">{t('prStatus.pending')}</span>;
 }
 
 export function PrInfoView({ pr }: PrInfoViewProps) {
diff --git a/apps/desktop/src/renderer/src/components/features/pr/tabs/PrTabs.tsx b/apps/desktop/src/renderer/src/components/features/pr/tabs/PrTabs.tsx
index 1287777..63d31b9 100644
--- a/apps/desktop/src/renderer/src/components/features/pr/tabs/PrTabs.tsx
+++ b/apps/desktop/src/renderer/src/components/features/pr/tabs/PrTabs.tsx
@@ -1,7 +1,7 @@
 import { useTranslation } from 'react-i18next';
-import { PersonIcon, WhitespaceIcon } from '../../../common/icons';
+import { ChatIcon, PersonIcon, WhitespaceIcon } from '../../../common/icons';
 
-export type PrTab = 'diff' | 'comments' | 'drafts' | 'commits' | 'info';
+export type PrTab = 'diff' | 'activity' | 'drafts' | 'commits' | 'info';
 
 /**
  * PR 详情 tab 栏：diff / 评论 / 草稿 / 提交 / 信息（带计数徽标），diff tab 时右侧附带
@@ -14,6 +14,8 @@ export function PrTabs({
   commitCount,
   totalDraftCount,
   publishableCount,
+  activityTimeline,
+  onNewComment,
   showWhitespace,
   onToggleWhitespace,
   showBlame,
@@ -27,6 +29,10 @@ export function PrTabs({
   commitCount: number | null;
   totalDraftCount: number;
   publishableCount: number;
+  /** 该平台是否提供活动时间线（见 capabilities.activityTimeline）；否则该 tab 标题退化为「评论」 */
+  activityTimeline: boolean;
+  /** 活动标签页右侧「评论」按钮：新建一条不锚到文件的评论 */
+  onNewComment: () => void;
   showWhitespace: boolean;
   onToggleWhitespace: () => void;
   showBlame: boolean;
@@ -46,15 +52,16 @@ export function PrTabs({
       >
         {t('mainPane.tabDiff')}
       </button>
-      {/* comments 在 commits 前：评审决断时评论的权重大于 commit 时间线 */}
+      {/* 活动时间线（评论 + 提交 + 评审决断）在 commits 前：评审决断时讨论权重大于纯 commit 列表。
+          角标仍取评论数——讨论量最具行动指引，提交另有独立 tab 计数。 */}
       <button
         type="button"
-        className={`pr-tab ${tab === 'comments' ? 'active' : ''}`}
-        onClick={() => onTab('comments')}
+        className={`pr-tab ${tab === 'activity' ? 'active' : ''}`}
+        onClick={() => onTab('activity')}
         role="tab"
-        aria-selected={tab === 'comments'}
+        aria-selected={tab === 'activity'}
       >
-        {t('mainPane.tabComments')}
+        {t(activityTimeline ? 'mainPane.tabActivity' : 'mainPane.tabComments')}
         <TabCountBadge
           count={commentCount}
           ariaLabel={(n) => t('mainPane.commentCountAria', { count: n })}
@@ -104,6 +111,13 @@ export function PrTabs({
       >
         {t('mainPane.tabInfo')}
       </button>
+      {tab === 'activity' && (
+        <div className="pr-tabs-right">
+          <button type="button" className="pr-tab-action-btn" onClick={onNewComment}>
+            <ChatIcon /> {t('mainPane.newComment')}
+          </button>
+        </div>
+      )}
       {tab === 'diff' && (
         <div className="pr-tabs-right">
           <button
diff --git a/apps/desktop/src/renderer/src/components/features/pr/tabs/activity/ActivityPanel.tsx b/apps/desktop/src/renderer/src/components/features/pr/tabs/activity/ActivityPanel.tsx
new file mode 100644
index 0000000..0e4b9a1
--- /dev/null
+++ b/apps/desktop/src/renderer/src/components/features/pr/tabs/activity/ActivityPanel.tsx
@@ -0,0 +1,337 @@
+import { useEffect, useMemo, useState, type ReactElement } from 'react';
+import { useTranslation } from 'react-i18next';
+import type {
+  PlatformCapabilities,
+  PrActivityEvent,
+  PrActivityKind,
+  PrComment,
+  PrCommit,
+  StoredPullRequest,
+} from '@meebox/shared';
+import { invoke, subscribe } from '../../../../../api';
+import { formatBackendError, type FormattedError } from '../../../../../errors';
+import { Avatar } from '../../../../common/Avatar';
+import { ApproveIcon, ChatIcon, CloseIcon, CommitIcon, NeedsWorkIcon } from '../../../../common/icons';
+import { PaneLoading } from '../../../../common/Loading';
+import { CommentComposer } from '../comments/CommentComposer';
+import {
+  CommentItem,
+  formatExactTime,
+  formatRelativeTime,
+  sameCommentList,
+} from '../comments/CommentItem';
+
+interface ActivityPanelProps {
+  pr: StoredPullRequest;
+  /** 顶层评论数（不含 replies）拉取成功后回调，供父组件 tab 角标用 */
+  onCommentsLoaded?: (count: number) => void;
+  /** 活动连接能力位；此处用 commentHardBreaks 决定评论是否启用 remark-breaks。 */
+  capabilities?: PlatformCapabilities;
+  /** 是否展开「新建评论」编辑框（由标签栏「评论」按钮控制，出现在时间线顶部） */
+  composing?: boolean;
+  /** 新建评论编辑框收起（取消 / 发布成功）回调 */
+  onComposeClose?: () => void;
+  /** 当前 PAT 用户名（新建评论编辑框头像用） */
+  currentUserName?: string | null;
+}
+
+/** 三路数据 + 其配对 PR 一起冻结，跨 poll 稳定引用，给评论树（含内联 Monaco）稳定身份避免重渲染。 */
+interface ActivityView {
+  pr: StoredPullRequest;
+  comments: PrComment[];
+  commits: PrCommit[];
+  activity: PrActivityEvent[];
+}
+
+/** 按 id 列表逐项比对（顺序敏感）。commits 用 sha、activity 用 remoteId，相等则跳过 setState 让 React bail。 */
+function sameIds<T>(a: readonly T[], b: readonly T[], id: (x: T) => string): boolean {
+  if (a.length !== b.length) return false;
+  for (let i = 0; i < a.length; i++) {
+    if (id(a[i]!) !== id(b[i]!)) return false;
+  }
+  return true;
+}
+
+/**
+ * PR 活动时间线（原「评论」标签页演进而来）。把三路数据按时间归并成一条时间线：
+ *   1. 评论（summary + inline，含 replies / 编辑 / 删除 / 内联代码，沿用 {@link CommentItem}）
+ *   2. 提交更新（{@link PrCommit}）
+ *   3. reviewer 评审决断事件（approve / needs-work / unapprove / dismiss，{@link PrActivityEvent}）
+ *
+ * 排序沿用评论页规则：**按时间倒序（newest first）**，最新动态在顶部。评论数据源与 DiffView 的 inline
+ * 评论同一份（`diff:listComments`，main 端有 pr_updated_at 缓存）；提交 / 决断各走自己的 IPC，二者
+ * 为增益信息，单独失败不影响评论时间线（catch 降级为空）。
+ *
+ * 切 PR 时不立刻清空（stale-while-loading）：旧时间线继续渲染、上盖 loading 遮罩，新数据 ready 后
+ * 整体替换，消除「先闪加载中再渲新」的空窗。
+ */
+export function ActivityPanel({
+  pr,
+  onCommentsLoaded,
+  capabilities,
+  composing = false,
+  onComposeClose,
+  currentUserName,
+}: ActivityPanelProps) {
+  // 评论换行：GitHub/Bitbucket hard-break；GitLab CommonMark 软换行。缺省回退 true。
+  const hardBreaks = capabilities?.commentHardBreaks ?? true;
+  // 差异化：GitHub/Bitbucket 渲染评论+提交+决断的活动时间线；GitLab（activityTimeline=false）退化为
+  // 纯评论视图（不拉提交/决断、沿用「评论」文案）。缺省（capabilities 未到）保守按纯评论。
+  const showTimeline = capabilities?.activityTimeline ?? false;
+  // 文案命名空间：时间线模式用 activityPanel.*，纯评论模式沿用 commentsPanel.*（保持 GitLab 原体验）。
+  const ns = showTimeline ? 'activityPanel' : 'commentsPanel';
+  const { t } = useTranslation();
+  const [view, setView] = useState<ActivityView | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState<FormattedError | null>(null);
+
+  useEffect(() => {
+    let cancelled = false;
+    setLoading(true);
+    setError(null);
+    const fetchAll = async (): Promise<void> => {
+      try {
+        // 评论是核心（失败=整块错误）；提交 / 决断是增益，单独失败 catch 成空，时间线照常展示评论。
+        // 纯评论模式（GitLab）跳过提交 / 决断拉取。
+        const [comments, commits, activity] = await Promise.all([
+          invoke('diff:listComments', { localId: pr.localId, force: true }),
+          showTimeline
+            ? invoke('diff:listCommits', { localId: pr.localId }).catch(() => [] as PrCommit[])
+            : Promise.resolve([] as PrCommit[]),
+          showTimeline
+            ? invoke('diff:listActivity', { localId: pr.localId }).catch(
+                () => [] as PrActivityEvent[],
+              )
+            : Promise.resolve([] as PrActivityEvent[]),
+        ]);
+        if (cancelled) return;
+        // 三路都与上次相等：保留旧 view 引用让 React bail（poll 无实质变化时不重渲时间线）。
+        setView((prev) =>
+          prev &&
+          prev.pr.localId === pr.localId &&
+          sameCommentList(prev.comments, comments) &&
+          sameIds(prev.commits, commits, (c) => c.sha) &&
+          sameIds(prev.activity, activity, (a) => a.remoteId)
+            ? prev
+            : { pr, comments, commits, activity },
+        );
+        setLoading(false);
+        onCommentsLoaded?.(comments.length);
+      } catch (e) {
+        if (!cancelled) {
+          setError(formatBackendError(e));
+          setLoading(false);
+        }
+      }
+    };
+    void fetchAll();
+    // 用户回复 / 编辑 / 删除 / 发布草稿后 main 广播 comments:changed → 重拉
+    const unsub = subscribe('comments:changed', (e) => {
+      if (e.localId === pr.localId) void fetchAll();
+    });
+    return () => {
+      cancelled = true;
+      unsub();
+    };
+    // onCommentsLoaded 故意不放依赖：父组件每次 render 都会重传新 ref，会触发误重拉
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [pr.localId, showTimeline]);
+
+  const viewPr = view?.pr;
+  // inline 评论自动挂 Monaco 上限：按 createdAt 倒序后的前 N 条 inline 直接挂；超额走 click-to-expand。
+  // 跟评论页一致取 10——一屏内大概看完，再多需主动展开。
+  const autoExpandSet = useMemo(() => {
+    const out = new Set<string>();
+    const inlineByNewest = (view?.comments ?? [])
+      .filter((c) => c.anchor)
+      .sort((a, b) => b.createdAt.localeCompare(a.createdAt));
+    for (let i = 0; i < inlineByNewest.length && i < 10; i++) out.add(inlineByNewest[i]!.remoteId);
+    return out;
+  }, [view]);
+
+  // 归并三路为时间线条目并按时间倒序。deps 全是稳定引用（view 经上面三路相等比对跳过后不变、
+  // autoExpandSet 随 view）→ poll 无变化时整条时间线（含内联 Monaco）元素身份不变，React 跳过重渲。
+  const timeline = useMemo<ReactElement[]>(() => {
+    if (!viewPr || !view) return [];
+    type Row = { key: string; at: number; node: ReactElement };
+    const rows: Row[] = [];
+    for (const c of view.comments) {
+      rows.push({
+        key: `comment:${c.remoteId}`,
+        at: Date.parse(c.createdAt) || 0,
+        node: (
+          <CommentItem
+            key={`comment:${c.remoteId}`}
+            comment={c}
+            pr={viewPr}
+            depth={0}
+            autoExpandCode={autoExpandSet.has(c.remoteId)}
+            hardBreaks={hardBreaks}
+            timeline={showTimeline}
+          />
+        ),
+      });
+    }
+    for (const cm of view.commits) {
+      rows.push({
+        key: `commit:${cm.sha}`,
+        at: Date.parse(cm.committedAt || cm.authoredAt) || 0,
+        node: <CommitEvent key={`commit:${cm.sha}`} commit={cm} pr={viewPr} />,
+      });
+    }
+    for (const ev of view.activity) {
+      rows.push({
+        key: `review:${ev.remoteId}`,
+        at: Date.parse(ev.createdAt) || 0,
+        node: <ReviewEvent key={`review:${ev.remoteId}`} event={ev} pr={viewPr} />,
+      });
+    }
+    // newest first；稳定排序下同刻条目按 评论→提交→决断 入队序排列
+    rows.sort((a, b) => b.at - a.at);
+    return rows.map((r) => r.node);
+  }, [view, viewPr, autoExpandSet, hardBreaks, showTimeline]);
+
+  // 首载失败 / 切 PR 失败（无可信展示内容，或现有 view 属于旧 PR）：整块错误，不拿旧 PR 内容冒充新的。
+  if (error && (!view || view.pr.localId !== pr.localId)) {
+    return (
+      <div className="pr-comments-panel">
+        <div className="pr-comments-scroll">
+          <div className="pr-comments-error" role="alert">
+            <strong>{t(`${ns}.loadError`, { title: error.title })}</strong>
+            <pre>{error.detail}</pre>
+          </div>
+        </div>
+      </div>
+    );
+  }
+
+  return (
+    <div className="pr-comments-panel">
+      <div className="pr-comments-scroll">
+        {(composing || (view && timeline.length > 0)) && (
+          <ul className="pr-comments-list pr-activity-list">
+            {/* 新建评论编辑框作为时间线首个节点：与其它条目同款图标节点 + 头像，编辑框缩进挂在轨上。 */}
+            {composing && (
+              <li className="pr-comment pr-comment-timeline pr-comment-depth-0">
+                <div className="pr-activity-item pr-activity-comment-head">
+                  <span className="pr-activity-icon pr-activity-icon-comment" aria-hidden="true">
+                    <ChatIcon size={18} />
+                  </span>
+                  <Avatar
+                    connectionId={pr.connectionId}
+                    slug={currentUserName ?? ''}
+                    displayName={currentUserName ?? ''}
+                    size={22}
+                  />
+                </div>
+                <div className="pr-activity-compose-card">
+                  <CommentComposer
+                    prLocalId={pr.localId}
+                    onCancel={() => onComposeClose?.()}
+                    onPosted={() => onComposeClose?.()}
+                  />
+                </div>
+              </li>
+            )}
+            {view ? timeline : null}
+          </ul>
+        )}
+        {view && timeline.length === 0 && !composing && !loading && (
+          <p className="muted">{t(`${ns}.empty`)}</p>
+        )}
+      </div>
+      {/* 加载遮罩盖住旧内容（或首载空面板），ready 后整体替换。PaneLoading 默认 delayMs=150：
+          命中缓存的快切换遮罩根本不出现、旧内容直接换新（零闪）；只有慢加载才显 spinner。 */}
+      {loading && <PaneLoading overlay label={t(`${ns}.loading`)} />}
+    </div>
+  );
+}
+
+/** 时间线上的提交事件：commit 图标 + 短 SHA + 主题 + 作者 + 时间；可点击跳远端 commit 页。 */
+function CommitEvent({ commit, pr }: { commit: PrCommit; pr: StoredPullRequest }) {
+  const { t } = useTranslation();
+  const isMerge = commit.parents.length > 1;
+  const subject = commit.message.split('\n', 1)[0]!;
+  const open = (): void => {
+    if (commit.url) window.open(commit.url, '_blank', 'noreferrer');
+  };
+  return (
+    <li
+      className={`pr-activity-item pr-activity-commit ${commit.url ? 'pr-activity-clickable' : ''}`}
+      onClick={open}
+      title={commit.message}
+    >
+      <span className="pr-activity-icon pr-activity-icon-commit" aria-hidden="true">
+        <CommitIcon size={18} />
+      </span>
+      {/* 作者展示与评论主体人对齐：同尺寸头像 + 加粗名，不做差异化 */}
+      <Avatar
+        connectionId={pr.connectionId}
+        slug={commit.author.slug ?? commit.author.name}
+        displayName={commit.author.displayName}
+        avatarUrl={commit.author.avatarUrl}
+        size={22}
+      />
+      <div className="pr-activity-main">
+        <span className="pr-activity-actor">{commit.author.displayName}</span>
+        <span className="pr-activity-commit-subject">{subject}</span>
+        {isMerge && (
+          <span
+            className="pr-activity-merge-tag"
+            title={t('activityPanel.mergeCommit', { parents: commit.parents.length })}
+          >
+            merge
+          </span>
+        )}
+        <code className="pr-activity-sha">{commit.abbreviatedSha}</code>
+      </div>
+      <time
+        className="pr-activity-time muted time-tip"
+        dateTime={commit.committedAt}
+        data-tip={formatExactTime(commit.committedAt || commit.authoredAt)}
+      >
+        {formatRelativeTime(commit.committedAt || commit.authoredAt)}
+      </time>
+    </li>
+  );
+}
+
+/** kind → 图标 + 语义色 class。approved 绿、needsWork 琥珀、unapproved/dismissed 中性。 */
+const REVIEW_ICON: Record<PrActivityKind, ReactElement> = {
+  approved: <ApproveIcon size={18} />,
+  needsWork: <NeedsWorkIcon size={18} />,
+  unapproved: <CloseIcon size={18} />,
+  dismissed: <CloseIcon size={18} />,
+};
+
+/** 时间线上的评审决断事件：actor + 判定动词 + 时间。 */
+function ReviewEvent({ event, pr }: { event: PrActivityEvent; pr: StoredPullRequest }) {
+  const { t } = useTranslation();
+  return (
+    <li className={`pr-activity-item pr-activity-review pr-activity-review-${event.kind}`}>
+      <span className={`pr-activity-icon pr-activity-icon-${event.kind}`} aria-hidden="true">
+        {REVIEW_ICON[event.kind]}
+      </span>
+      <Avatar
+        connectionId={pr.connectionId}
+        slug={event.actor.slug ?? event.actor.name}
+        displayName={event.actor.displayName}
+        avatarUrl={event.actor.avatarUrl}
+        size={22}
+      />
+      <div className="pr-activity-main">
+        <span className="pr-activity-actor">{event.actor.displayName}</span>
+        <span className={`pr-activity-chip pr-activity-chip-${event.kind}`}>
+          {t(`activityPanel.verb.${event.kind}`)}
+        </span>
+      </div>
+      <time
+        className="pr-activity-time muted time-tip"
+        dateTime={event.createdAt}
+        data-tip={formatExactTime(event.createdAt)}
+      >
+        {formatRelativeTime(event.createdAt)}
+      </time>
+    </li>
+  );
+}
diff --git a/apps/desktop/src/renderer/src/components/features/pr/tabs/comments/CommentComposer.tsx b/apps/desktop/src/renderer/src/components/features/pr/tabs/comments/CommentComposer.tsx
new file mode 100644
index 0000000..7483cef
--- /dev/null
+++ b/apps/desktop/src/renderer/src/components/features/pr/tabs/comments/CommentComposer.tsx
@@ -0,0 +1,91 @@
+import { useEffect, useRef, useState } from 'react';
+import { useTranslation } from 'react-i18next';
+import { invoke } from '../../../../../api';
+
+interface CommentComposerProps {
+  prLocalId: string;
+  onCancel: () => void;
+  /** 发布成功后调用（收起编辑框；时间线通过 comments:changed 事件自动刷新，新评论出现在顶部） */
+  onPosted: () => void;
+}
+
+/**
+ * 新建 summary（不锚到文件）评论的编辑框：textarea + 发送/取消。出现在活动时间线最上方。
+ * Cmd/Ctrl+Enter 发送，Esc 取消；空 body disabled 发送。版式复用回复编辑框样式。
+ */
+export function CommentComposer({ prLocalId, onCancel, onPosted }: CommentComposerProps) {
+  const { t } = useTranslation();
+  const [body, setBody] = useState('');
+  const [posting, setPosting] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+  const textareaRef = useRef<HTMLTextAreaElement | null>(null);
+
+  // mount 自动 focus，提升输入体感
+  useEffect(() => {
+    textareaRef.current?.focus();
+  }, []);
+
+  const canSave = body.trim().length > 0 && !posting;
+
+  const handleSave = async (): Promise<void> => {
+    if (!canSave) return;
+    setPosting(true);
+    setError(null);
+    try {
+      await invoke('comments:create', { localId: prLocalId, body });
+      onPosted();
+    } catch (e) {
+      setError(e instanceof Error ? e.message : String(e));
+    } finally {
+      setPosting(false);
+    }
+  };
+
+  const onKeyDown = (e: React.KeyboardEvent<HTMLTextAreaElement>): void => {
+    if (e.nativeEvent.isComposing) return;
+    if ((e.metaKey || e.ctrlKey) && e.key === 'Enter') {
+      e.preventDefault();
+      void handleSave();
+    } else if (e.key === 'Escape') {
+      e.preventDefault();
+      onCancel();
+    }
+  };
+
+  return (
+    <div className="comment-reply-editor">
+      <textarea
+        ref={textareaRef}
+        className="comment-reply-textarea"
+        value={body}
+        onChange={(e) => setBody(e.target.value)}
+        onKeyDown={onKeyDown}
+        placeholder={t('commentComposer.placeholder')}
+        rows={3}
+        disabled={posting}
+        aria-label={t('commentComposer.textareaAria')}
+      />
+      <div className="comment-reply-actions">
+        <button
+          type="button"
+          className="comment-reply-btn comment-reply-btn-primary"
+          onClick={() => void handleSave()}
+          disabled={!canSave}
+          title={canSave ? t('commentComposer.sendTitle') : t('commentComposer.emptyTitle')}
+        >
+          {posting ? t('commentComposer.sending') : t('commentComposer.send')}
+        </button>
+        <button
+          type="button"
+          className="comment-reply-btn"
+          onClick={onCancel}
+          disabled={posting}
+          title={t('commentComposer.cancelTitle')}
+        >
+          {t('common.cancel')}
+        </button>
+        {error && <span className="comment-reply-error">{error}</span>}
+      </div>
+    </div>
+  );
+}
diff --git a/apps/desktop/src/renderer/src/components/features/pr/tabs/comments/CommentItem.tsx b/apps/desktop/src/renderer/src/components/features/pr/tabs/comments/CommentItem.tsx
new file mode 100644
index 0000000..e89b35c
--- /dev/null
+++ b/apps/desktop/src/renderer/src/components/features/pr/tabs/comments/CommentItem.tsx
@@ -0,0 +1,350 @@
+import { lazy, Suspense, useMemo, useState } from 'react';
+import { useTranslation } from 'react-i18next';
+import ReactMarkdown from 'react-markdown';
+import remarkBreaks from 'remark-breaks';
+import remarkGfm from 'remark-gfm';
+import type { PrComment, StoredPullRequest } from '@meebox/shared';
+import { invoke } from '../../../../../api';
+import i18n from '../../../../../i18n';
+import { REMOTE_REHYPE_PLUGINS } from '../../../../../lib/markdown';
+import { Avatar } from '../../../../common/Avatar';
+import { makeBitbucketImageFor, transformBitbucketUrl } from '../../../../common/BitbucketImage';
+import { ChatIcon } from '../../../../common/icons';
+import { CommentEditEditor } from './CommentEditEditor';
+import { CommentReplyEditor } from './CommentReplyEditor';
+import { ConfirmModal } from '../../../../common/ConfirmModal';
+import { mermaidComponents } from '../../../../common/markdownMermaid';
+// 行内代码上下文用 Monaco，懒加载随 DiffView 同一套 Monaco chunk 按需拉取，不进入口包。
+const InlineCodeContext = lazy(() =>
+  import('./InlineCodeContext').then((m) => ({ default: m.InlineCodeContext })),
+);
+
+/**
+ * 评论树结构相等比较（按 remoteId + 正文 + version + 编辑/删除权限 + 递归 replies）。poll 多数返回
+ * 内容不变的评论：相等就跳过 setState、保留旧引用，让 React bail-out，避免整棵评论树（含内联
+ * Monaco）无谓重渲染（刷新抖动）。
+ */
+export function sameCommentList(a: readonly PrComment[], b: readonly PrComment[]): boolean {
+  if (a.length !== b.length) return false;
+  for (let i = 0; i < a.length; i++) {
+    const x = a[i]!;
+    const y = b[i]!;
+    if (
+      x.remoteId !== y.remoteId ||
+      x.body !== y.body ||
+      x.version !== y.version ||
+      x.canEdit !== y.canEdit ||
+      x.canDelete !== y.canDelete ||
+      !sameCommentList(x.replies, y.replies)
+    ) {
+      return false;
+    }
+  }
+  return true;
+}
+
+/**
+ * 嵌套回复的最大缩进层级：满此层级后继续递归但**不再加缩进**（拉平展示），避免深嵌套把内容挤到
+ * 右侧极窄。depth 0 为顶层评论；depth 1..MAX 逐级缩进，超过 MAX 的更深回复一律平铺在 MAX 层缩进上，
+ * 仍按作者归属可读。Bitbucket 实际只一层 reply，GitHub / GitLab 可深嵌套，故设上限。
+ */
+const MAX_REPLY_DEPTH = 5;
+
+/**
+ * 单条评论 + 嵌套 replies。inline 评论顶部显示 `path:line side` chip 区分锚点位置；
+ * summary 评论不挂 chip。replies 走递归，depth 控制左侧缩进；满 MAX_REPLY_DEPTH 层后拉平
+ * （不再加缩进，见该常量）。
+ *
+ * `timeline` 模式（活动时间线，GitHub/Bitbucket）下的**顶层评论**改走时间线行版式：与其它事件统一
+ * 「评论图标 + 头像 + 加粗作者名 + 『评论』动词 + 时间」标题，正文整体缩进成挂在时间线轨上的卡片。
+ * 非 timeline（GitLab 纯评论视图）或回复（depth>0）维持原卡片版式。
+ */
+export function CommentItem({
+  comment,
+  pr,
+  depth,
+  autoExpandCode = false,
+  hardBreaks,
+  timeline = false,
+}: {
+  comment: PrComment;
+  pr: StoredPullRequest;
+  depth: number;
+  /** 顶层 (depth=0) 由父组件按 CAP 决定 true/false；replies 总是 false (不渲染 code) */
+  autoExpandCode?: boolean;
+  hardBreaks: boolean;
+  /** 是否处于活动时间线模式（仅影响顶层评论版式，见上方说明） */
+  timeline?: boolean;
+}) {
+  const { t } = useTranslation();
+  // 评论 body 内嵌图片走 IPC 代理 (Bitbucket 私有资源需 PAT 鉴权)
+  const mdComponents = useMemo(
+    () => ({ ...mermaidComponents, img: makeBitbucketImageFor(pr.localId, pr.url) }),
+    [pr.localId, pr.url],
+  );
+  const [replyOpen, setReplyOpen] = useState(false);
+  const [editOpen, setEditOpen] = useState(false);
+  const [confirmDelete, setConfirmDelete] = useState(false);
+  const [deleting, setDeleting] = useState(false);
+  const [deleteError, setDeleteError] = useState<string | null>(null);
+
+  // 删除/编辑条件 main 端预判好了 (annotateOwnership)。renderer 直读 flag，
+  // 不再自己比对 author / version / replies
+  const canDelete = comment.canDelete === true;
+  const canEdit = comment.canEdit === true;
+
+  const handleDelete = async (): Promise<void> => {
+    if (!canDelete || comment.version === undefined) return;
+    setConfirmDelete(false);
+    setDeleting(true);
+    setDeleteError(null);
+    try {
+      await invoke('comments:delete', {
+        localId: pr.localId,
+        commentId: comment.remoteId,
+        version: comment.version,
+      });
+      // 成功 → main 端清 cache + 广播 comments:changed → 本面板 useEffect 重拉，
+      // 这条评论自然从列表里消失，不用手动维护本地 state
+    } catch (e) {
+      setDeleteError(e instanceof Error ? e.message : String(e));
+      setDeleting(false);
+    }
+  };
+
+  // inline 评论锚点 chip：path:line + 侧别 (old=base / new=head)，让用户在评论里定位到代码位置
+  const anchorChip = comment.anchor ? (
+    <span
+      className={`pr-comment-anchor pr-comment-anchor-${comment.anchor.side}`}
+      title={t('commentsPanel.anchorTitle', {
+        side: comment.anchor.side === 'old' ? 'base' : 'head',
+        lineType: comment.anchor.lineType,
+      })}
+    >
+      <code>{comment.anchor.path}</code>:{comment.anchor.line}
+    </span>
+  ) : null;
+
+  // inline 评论：在正文上方嵌一段代码上下文 (Monaco read-only)。replies (depth > 0) 不重复展示。
+  const inlineCode =
+    comment.anchor && depth === 0 ? (
+      <Suspense
+        fallback={<div className="pane-loading muted">{t('commentsPanel.loadingCodeContext')}</div>}
+      >
+        <InlineCodeContext pr={pr} anchor={comment.anchor} autoExpand={autoExpandCode} />
+      </Suspense>
+    ) : null;
+
+  // 编辑态：textarea 占位替换 markdown 正文；非编辑态：渲染 markdown
+  const bodyOrEdit =
+    editOpen && typeof comment.version === 'number' ? (
+      <CommentEditEditor
+        prLocalId={pr.localId}
+        commentId={comment.remoteId}
+        version={comment.version}
+        initialBody={comment.body}
+        onCancel={() => setEditOpen(false)}
+        onSaved={() => setEditOpen(false)}
+      />
+    ) : (
+      <div className="pr-comment-body markdown">
+        {/* hardBreaks（Bitbucket/GitHub）挂 remarkBreaks 单 \n→<br>；GitLab CommonMark 不挂 */}
+        <ReactMarkdown
+          remarkPlugins={hardBreaks ? [remarkGfm, remarkBreaks] : [remarkGfm]}
+          rehypePlugins={REMOTE_REHYPE_PLUGINS}
+          components={mdComponents}
+          urlTransform={transformBitbucketUrl}
+        >
+          {comment.body}
+        </ReactMarkdown>
+      </div>
+    );
+
+  // 操作行：编辑态隐藏所有按钮（避免跟编辑器底部按钮组重复）
+  const foot = !editOpen ? (
+    <div className="pr-comment-foot">
+      {!replyOpen && (
+        <button type="button" className="pr-comment-reply-btn" onClick={() => setReplyOpen(true)}>
+          {t('commentsPanel.reply')}
+        </button>
+      )}
+      {canEdit && !replyOpen && (
+        <button
+          type="button"
+          className="pr-comment-edit-btn"
+          onClick={() => setEditOpen(true)}
+          title={t('commentsPanel.editTitle')}
+        >
+          {t('common.edit')}
+        </button>
+      )}
+      {/* 删除按钮在最后，跟其它按钮风格对齐 — disable 期间文案变"删除中…" */}
+      {canDelete && !replyOpen && (
+        <button
+          type="button"
+          className="pr-comment-delete-btn"
+          onClick={() => setConfirmDelete(true)}
+          disabled={deleting}
+          title={t('commentsPanel.deleteTitle')}
+        >
+          {deleting ? t('commentsPanel.deleting') : t('common.delete')}
+        </button>
+      )}
+    </div>
+  ) : null;
+
+  const deleteErrorEl = deleteError ? (
+    <div className="pr-comment-delete-error" role="alert">
+      {t('commentsPanel.deleteFailed', { msg: deleteError })}
+      <button
+        type="button"
+        className="pr-comment-delete-error-dismiss"
+        onClick={() => setDeleteError(null)}
+        aria-label={t('commentsPanel.dismissErrorAria')}
+        title={t('commentsPanel.dismissErrorTitle')}
+      >
+        ✕
+      </button>
+    </div>
+  ) : null;
+
+  const replyEditor = replyOpen ? (
+    <CommentReplyEditor
+      prLocalId={pr.localId}
+      // 回复目标抽象（threadId）：GitLab=discussion id（reply 必需）；Bitbucket 空 / GitHub=remoteId → 回退 remoteId。
+      parentCommentId={comment.threadId ?? comment.remoteId}
+      onCancel={() => setReplyOpen(false)}
+      onPosted={() => setReplyOpen(false)}
+    />
+  ) : null;
+
+  const repliesEl =
+    comment.replies.length > 0 ? (
+      // 满 MAX_REPLY_DEPTH 层后用 pr-comments-flat 取代 pr-comments-replies（不再缩进 / 左边框）→
+      // 更深回复拉平在该层缩进上；pr-comments-flat 据此给同层级相邻评论加横向分割线区分。
+      <ul
+        className={`pr-comments-list ${depth < MAX_REPLY_DEPTH ? 'pr-comments-replies' : 'pr-comments-flat'}`}
+      >
+        {comment.replies.map((r) => (
+          <CommentItem
+            key={r.remoteId}
+            comment={r}
+            pr={pr}
+            depth={depth + 1}
+            hardBreaks={hardBreaks}
+          />
+        ))}
+      </ul>
+    ) : null;
+
+  const confirmModalEl = confirmDelete ? (
+    <ConfirmModal
+      title={t('commentsPanel.deleteConfirmTitle')}
+      message={t('commentsPanel.deleteConfirmMessage')}
+      confirmLabel={t('common.delete')}
+      cancelLabel={t('common.cancel')}
+      danger
+      onConfirm={() => void handleDelete()}
+      onCancel={() => setConfirmDelete(false)}
+    />
+  ) : null;
+
+  // 时间线模式的顶层评论：与其它事件统一的标题行（图标 + 头像 + 作者 + 『评论』+ 时间），正文挂成缩进卡片。
+  if (timeline && depth === 0) {
+    return (
+      <li className="pr-comment pr-comment-timeline pr-comment-depth-0">
+        <div className="pr-activity-item pr-activity-comment-head">
+          <span className="pr-activity-icon pr-activity-icon-comment" aria-hidden="true">
+            <ChatIcon size={18} />
+          </span>
+          <Avatar
+            connectionId={pr.connectionId}
+            slug={comment.author.slug ?? comment.author.name}
+            displayName={comment.author.displayName}
+            avatarUrl={comment.author.avatarUrl}
+            size={22}
+          />
+          <div className="pr-activity-main">
+            <span className="pr-activity-actor">{comment.author.displayName}</span>
+            <span className="pr-activity-verb">{t('activityPanel.verb.commented')}</span>
+            {anchorChip}
+          </div>
+          <time
+            className="pr-activity-time muted time-tip"
+            dateTime={comment.createdAt}
+            data-tip={formatExactTime(comment.createdAt)}
+          >
+            {formatRelativeTime(comment.createdAt)}
+          </time>
+        </div>
+        <div className="pr-comment-card">
+          {inlineCode}
+          {bodyOrEdit}
+          {foot}
+          {deleteErrorEl}
+          {replyEditor}
+          {repliesEl}
+        </div>
+        {confirmModalEl}
+      </li>
+    );
+  }
+
+  return (
+    <li className={`pr-comment pr-comment-depth-${String(Math.min(depth, MAX_REPLY_DEPTH))}`}>
+      <div className="pr-comment-head">
+        <Avatar
+          connectionId={pr.connectionId}
+          slug={comment.author.slug ?? comment.author.name}
+          displayName={comment.author.displayName}
+          avatarUrl={comment.author.avatarUrl}
+          size={22}
+        />
+        <span className="pr-comment-author">{comment.author.displayName}</span>
+        {anchorChip}
+        <time
+          className="pr-comment-time muted time-tip"
+          dateTime={comment.createdAt}
+          data-tip={formatExactTime(comment.createdAt)}
+        >
+          {formatRelativeTime(comment.createdAt)}
+        </time>
+      </div>
+      {inlineCode}
+      {bodyOrEdit}
+      {foot}
+      {deleteErrorEl}
+      {replyEditor}
+      {repliesEl}
+      {confirmModalEl}
+    </li>
+  );
+}
+
+/**
+ * 精确到秒的本地时间文案（`YYYY-MM-DD HH:mm:ss`），供时间标签 hover tooltip 展示实际时间点。
+ */
+export function formatExactTime(iso: string): string {
+  const ms = Date.parse(iso);
+  if (Number.isNaN(ms)) return iso;
+  const d = new Date(ms);
+  const pad = (n: number): string => String(n).padStart(2, '0');
+  return `${String(d.getFullYear())}-${pad(d.getMonth() + 1)}-${pad(d.getDate())} ${pad(d.getHours())}:${pad(d.getMinutes())}:${pad(d.getSeconds())}`;
+}
+
+/**
+ * 相对时间文案（刚刚 / N 分钟前 / …），一周以上回退本地日期。供评论与活动事件共用。
+ */
+export function formatRelativeTime(iso: string): string {
+  const t = Date.parse(iso);
+  if (Number.isNaN(t)) return iso;
+  const diffSec = Math.max(0, Math.round((Date.now() - t) / 1000));
+  if (diffSec < 60) return i18n.t('commentsPanel.justNow');
+  if (diffSec < 3600)
+    return i18n.t('commentsPanel.minutesAgo', { count: Math.round(diffSec / 60) });
+  if (diffSec < 86400)
+    return i18n.t('commentsPanel.hoursAgo', { count: Math.round(diffSec / 3600) });
+  if (diffSec < 86400 * 7)
+    return i18n.t('commentsPanel.daysAgo', { count: Math.round(diffSec / 86400) });
+  return new Date(t).toLocaleDateString();
+}
diff --git a/apps/desktop/src/renderer/src/components/features/pr/tabs/comments/CommentsPanel.tsx b/apps/desktop/src/renderer/src/components/features/pr/tabs/comments/CommentsPanel.tsx
deleted file mode 100644
index 4c968a4..0000000
--- a/apps/desktop/src/renderer/src/components/features/pr/tabs/comments/CommentsPanel.tsx
+++ /dev/null
@@ -1,415 +0,0 @@
-import { lazy, Suspense, useEffect, useMemo, useState } from 'react';
-import { useTranslation } from 'react-i18next';
-import ReactMarkdown from 'react-markdown';
-import remarkBreaks from 'remark-breaks';
-import remarkGfm from 'remark-gfm';
-import type { PlatformCapabilities, PrComment, StoredPullRequest } from '@meebox/shared';
-import { invoke, subscribe } from '../../../../../api';
-import i18n from '../../../../../i18n';
-import { formatBackendError, type FormattedError } from '../../../../../errors';
-import { REMOTE_REHYPE_PLUGINS } from '../../../../../lib/markdown';
-import { Avatar } from '../../../../common/Avatar';
-import { PaneLoading } from '../../../../common/Loading';
-import { makeBitbucketImageFor, transformBitbucketUrl } from '../../../../common/BitbucketImage';
-import { CommentEditEditor } from './CommentEditEditor';
-import { CommentReplyEditor } from './CommentReplyEditor';
-import { ConfirmModal } from '../../../../common/ConfirmModal';
-import { mermaidComponents } from '../../../../common/markdownMermaid';
-// 行内代码上下文用 Monaco，懒加载随 DiffView 同一套 Monaco chunk 按需拉取，不进入口包。
-const InlineCodeContext = lazy(() =>
-  import('./InlineCodeContext').then((m) => ({ default: m.InlineCodeContext })),
-);
-
-/**
- * 评论树结构相等比较（按 remoteId + 正文 + version + 编辑/删除权限 + 递归 replies）。poll 多数返回
- * 内容不变的评论：相等就跳过 setComments、保留旧引用，让 React bail-out，避免整棵评论树（含内联
- * Monaco）无谓重渲染（刷新抖动）。
- */
-function sameCommentList(a: readonly PrComment[], b: readonly PrComment[]): boolean {
-  if (a.length !== b.length) return false;
-  for (let i = 0; i < a.length; i++) {
-    const x = a[i]!;
-    const y = b[i]!;
-    if (
-      x.remoteId !== y.remoteId ||
-      x.body !== y.body ||
-      x.version !== y.version ||
-      x.canEdit !== y.canEdit ||
-      x.canDelete !== y.canDelete ||
-      !sameCommentList(x.replies, y.replies)
-    ) {
-      return false;
-    }
-  }
-  return true;
-}
-
-interface CommentsPanelProps {
-  pr: StoredPullRequest;
-  /** 拉取成功后回调，把顶层评论数 (不含 replies) 报给父组件用于 tab 角标 */
-  onCommentsLoaded?: (count: number) => void;
-  /** 活动连接能力位；此处用 commentHardBreaks 决定评论是否启用 remark-breaks。 */
-  capabilities?: PlatformCapabilities;
-}
-
-/**
- * PR 全量评论视图（独立标签页，跟 Diff inline 评论互补）。
- *
- * 数据来源 跟 DiffView 的 inline 评论同一份 (`diff:listComments`)，main 层有
- * `pr_updated_at` 缓存；进入本面板时优先回缓存，远端变更后失效自动重拉。
- *
- * 排版：summary 评论 (anchor=null) 跟 inline 评论 (anchor!=null) 都展示，inline
- * 顶部标 `path:line` chip 让用户知道这条评论锚在哪。replies 嵌套缩进 1 层渲染。
- */
-export function CommentsPanel({ pr, onCommentsLoaded, capabilities }: CommentsPanelProps) {
-  // 评论换行：GitHub/Bitbucket hard-break；GitLab CommonMark 软换行。缺省回退 true。
-  const hardBreaks = capabilities?.commentHardBreaks ?? true;
-  const { t } = useTranslation();
-  // 已展示的视图：评论与其配对的 pr 一起冻结。切 PR 时**不立刻清空**——旧视图继续渲染、上盖 loading
-  // 遮罩，新数据 ready 后整体替换（stale-while-loading），消除「先闪『加载中』再渲新」的空窗。
-  // pr 与评论必须配对：旧评论要用旧 PR 的上下文（图片代理 / 回复目标）渲染，且该 ref 跨 poll 稳定，
-  // 给评论树（含内联 Monaco）稳定引用避免重渲染。
-  const [view, setView] = useState<{ pr: StoredPullRequest; comments: PrComment[] } | null>(null);
-  const [loading, setLoading] = useState(true);
-  const [error, setError] = useState<FormattedError | null>(null);
-
-  useEffect(() => {
-    let cancelled = false;
-    setLoading(true);
-    setError(null);
-    // 不清 view：切 PR 期间旧评论继续显示、由遮罩盖住，避免空窗闪烁。
-    const fetchList = async (force: boolean): Promise<void> => {
-      try {
-        const list = await invoke('diff:listComments', { localId: pr.localId, force });
-        if (cancelled) return;
-        // 同 PR 且内容相等：保留旧 view 引用让 React bail（comments:changed 无实质变化时不重渲评论树）。
-        setView((prev) =>
-          prev && prev.pr.localId === pr.localId && sameCommentList(prev.comments, list)
-            ? prev
-            : { pr, comments: list },
-        );
-        setLoading(false);
-        onCommentsLoaded?.(list.length);
-      } catch (e) {
-        if (!cancelled) {
-          setError(formatBackendError(e));
-          setLoading(false);
-        }
-      }
-    };
-    void fetchList(true);
-    // 监听 main 端 comments:changed 事件 — 用户回复评论 / 其他 PR 操作触发评论
-    // 树变化时重拉远端最新 (force=true 跳过 cache 比对)
-    const unsub = subscribe('comments:changed', (e) => {
-      if (e.localId === pr.localId) void fetchList(true);
-    });
-    return () => {
-      cancelled = true;
-      unsub();
-    };
-    // onCommentsLoaded 故意不放依赖：父组件每次 render 都会重传新 ref，会触发误重拉
-    // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, [pr.localId]);
-
-  const viewPr = view?.pr;
-  // 按 createdAt **倒序** (newest first)：评论页主要给用户快速看最新动态用，
-  // 不是逐条对话回溯，最新在顶部更合理
-  const ordered = useMemo(
-    () => (view?.comments ?? []).slice().sort((a, b) => b.createdAt.localeCompare(a.createdAt)),
-    [view],
-  );
-  // inline 评论自动挂 Monaco 上限：前 N 条 (按倒序后的顺序，最新 N 个 inline) 直接
-  // 挂；超额走 click-to-expand 懒加载。CAP 取 10 跟用户感知节奏一致 —— 一屏内大
-  // 概看完，再多就需要主动展开
-  const AUTO_EXPAND_CAP = 10;
-  const autoExpandSet = useMemo(() => {
-    const out = new Set<string>();
-    let i = 0;
-    for (const c of ordered) {
-      if (c.anchor) {
-        if (i < AUTO_EXPAND_CAP) out.add(c.remoteId);
-        i++;
-      }
-    }
-    return out;
-  }, [ordered]);
-
-  // 缓存顶层评论元素列表：deps 全是稳定引用（ordered 经 sameCommentList 跳过后不变、viewPr 与评论配对
-  // 冻结、autoExpandSet 随 ordered）。poll 无评论变化时元素引用不变 → React 跳过整棵评论子树（含内联
-  // Monaco），消除刷新抖动。
-  const commentEls = useMemo(
-    () =>
-      viewPr
-        ? ordered.map((c) => (
-            <CommentItem
-              key={c.remoteId}
-              comment={c}
-              pr={viewPr}
-              depth={0}
-              autoExpandCode={autoExpandSet.has(c.remoteId)}
-              hardBreaks={hardBreaks}
-            />
-          ))
-        : [],
-    [ordered, viewPr, autoExpandSet, hardBreaks],
-  );
-
-  // 首载失败 / 切 PR 失败（无可信展示内容，或现有 view 属于旧 PR）：整块错误，不拿旧 PR 的评论冒充新的。
-  if (error && (!view || view.pr.localId !== pr.localId)) {
-    return (
-      <div className="pr-comments-panel">
-        <div className="pr-comments-scroll">
-          <div className="pr-comments-error" role="alert">
-            <strong>{t('commentsPanel.loadError', { title: error.title })}</strong>
-            <pre>{error.detail}</pre>
-          </div>
-        </div>
-      </div>
-    );
-  }
-
-  return (
-    <div className="pr-comments-panel">
-      <div className="pr-comments-scroll">
-        {view && ordered.length > 0 && <ul className="pr-comments-list">{commentEls}</ul>}
-        {view && ordered.length === 0 && !loading && (
-          <p className="muted">{t('commentsPanel.empty')}</p>
-        )}
-      </div>
-      {/* 加载遮罩盖住旧内容（或首载空面板），ready 后整体替换。PaneLoading 默认 delayMs=150：
-          命中本地缓存的快切换遮罩根本不出现、旧内容直接换新（零闪）；只有慢加载才显 spinner。 */}
-      {loading && <PaneLoading overlay label={t('commentsPanel.loading')} />}
-    </div>
-  );
-}
-
-/**
- * 嵌套回复的最大缩进层级：满此层级后继续递归但**不再加缩进**（拉平展示），避免深嵌套把内容挤到
- * 右侧极窄。depth 0 为顶层评论；depth 1..MAX 逐级缩进，超过 MAX 的更深回复一律平铺在 MAX 层缩进上，
- * 仍按作者归属可读。Bitbucket 实际只一层 reply，GitHub / GitLab 可深嵌套，故设上限。
- */
-const MAX_REPLY_DEPTH = 5;
-
-/**
- * 单条评论 + 嵌套 replies。inline 评论顶部显示 `path:line side` chip 区分锚点位置；
- * summary 评论不挂 chip。replies 走递归，depth 控制左侧缩进；满 MAX_REPLY_DEPTH 层后拉平
- * （不再加缩进，见该常量）。
- */
-function CommentItem({
-  comment,
-  pr,
-  depth,
-  autoExpandCode = false,
-  hardBreaks,
-}: {
-  comment: PrComment;
-  pr: StoredPullRequest;
-  depth: number;
-  /** 顶层 (depth=0) 由父组件按 CAP 决定 true/false；replies 总是 false (不渲染 code) */
-  autoExpandCode?: boolean;
-  hardBreaks: boolean;
-}) {
-  const { t } = useTranslation();
-  // 评论 body 内嵌图片走 IPC 代理 (Bitbucket 私有资源需 PAT 鉴权)
-  const mdComponents = useMemo(
-    () => ({ ...mermaidComponents, img: makeBitbucketImageFor(pr.localId, pr.url) }),
-    [pr.localId, pr.url],
-  );
-  const [replyOpen, setReplyOpen] = useState(false);
-  const [editOpen, setEditOpen] = useState(false);
-  const [confirmDelete, setConfirmDelete] = useState(false);
-  const [deleting, setDeleting] = useState(false);
-  const [deleteError, setDeleteError] = useState<string | null>(null);
-
-  // 删除/编辑条件 main 端预判好了 (annotateOwnership)。renderer 直读 flag，
-  // 不再自己比对 author / version / replies
-  const canDelete = comment.canDelete === true;
-  const canEdit = comment.canEdit === true;
-
-  const handleDelete = async (): Promise<void> => {
-    if (!canDelete || comment.version === undefined) return;
-    setConfirmDelete(false);
-    setDeleting(true);
-    setDeleteError(null);
-    try {
-      await invoke('comments:delete', {
-        localId: pr.localId,
-        commentId: comment.remoteId,
-        version: comment.version,
-      });
-      // 成功 → main 端清 cache + 广播 comments:changed → 本面板 useEffect 重拉，
-      // 这条评论自然从列表里消失，不用手动维护本地 state
-    } catch (e) {
-      setDeleteError(e instanceof Error ? e.message : String(e));
-      setDeleting(false);
-    }
-  };
-
-  return (
-    <li className={`pr-comment pr-comment-depth-${String(Math.min(depth, MAX_REPLY_DEPTH))}`}>
-      <div className="pr-comment-head">
-        <Avatar
-          connectionId={pr.connectionId}
-          slug={comment.author.slug ?? comment.author.name}
-          displayName={comment.author.displayName}
-          avatarUrl={comment.author.avatarUrl}
-          size={22}
-        />
-        <span className="pr-comment-author">{comment.author.displayName}</span>
-        {comment.anchor && (
-          // inline 评论锚点 chip：path:line + 侧别 (old=base / new=head)。
-          // 让用户在评论面板里也能定位到代码位置 (后续可点击跳 Diff 视图)
-          <span
-            className={`pr-comment-anchor pr-comment-anchor-${comment.anchor.side}`}
-            title={t('commentsPanel.anchorTitle', {
-              side: comment.anchor.side === 'old' ? 'base' : 'head',
-              lineType: comment.anchor.lineType,
-            })}
-          >
-            <code>{comment.anchor.path}</code>:{comment.anchor.line}
-          </span>
-        )}
-        <time className="pr-comment-time muted" dateTime={comment.createdAt}>
-          {formatRelativeTime(comment.createdAt)}
-        </time>
-      </div>
-      {/* inline 评论：在正文上方嵌一段代码上下文 (Monaco read-only)，锚定行高亮。
-          replies (depth > 0) 不重复展示，避免冗余 —— 父评论已经给了上下文。
-          autoExpandCode 由父组件按"最新 N 条"决定，超额条目用户点开才挂 editor */}
-      {comment.anchor && depth === 0 && (
-        <Suspense
-          fallback={
-            <div className="pane-loading muted">{t('commentsPanel.loadingCodeContext')}</div>
-          }
-        >
-          <InlineCodeContext pr={pr} anchor={comment.anchor} autoExpand={autoExpandCode} />
-        </Suspense>
-      )}
-      {/* 编辑态：textarea 占位替换 markdown 正文；非编辑态：渲染 markdown */}
-      {editOpen && typeof comment.version === 'number' ? (
-        <CommentEditEditor
-          prLocalId={pr.localId}
-          commentId={comment.remoteId}
-          version={comment.version}
-          initialBody={comment.body}
-          onCancel={() => setEditOpen(false)}
-          onSaved={() => setEditOpen(false)}
-        />
-      ) : (
-        <div className="pr-comment-body markdown">
-          {/* hardBreaks（Bitbucket/GitHub）挂 remarkBreaks 单 \n→<br>；GitLab CommonMark 不挂 */}
-          <ReactMarkdown
-            remarkPlugins={hardBreaks ? [remarkGfm, remarkBreaks] : [remarkGfm]}
-            rehypePlugins={REMOTE_REHYPE_PLUGINS}
-            components={mdComponents}
-            urlTransform={transformBitbucketUrl}
-          >
-            {comment.body}
-          </ReactMarkdown>
-        </div>
-      )}
-      {/* 操作行：编辑态隐藏所有按钮 (避免跟编辑器底部按钮组重复)；非编辑态展示
-          回复 / 编辑 / 删除三个按钮 */}
-      {!editOpen && (
-        <div className="pr-comment-foot">
-          {!replyOpen && (
-            <button
-              type="button"
-              className="pr-comment-reply-btn"
-              onClick={() => setReplyOpen(true)}
-            >
-              {t('commentsPanel.reply')}
-            </button>
-          )}
-          {canEdit && !replyOpen && (
-            <button
-              type="button"
-              className="pr-comment-edit-btn"
-              onClick={() => setEditOpen(true)}
-              title={t('commentsPanel.editTitle')}
-            >
-              {t('common.edit')}
-            </button>
-          )}
-          {/* 删除按钮在最后，跟其它按钮风格对齐 — disable 期间文案变"删除中…" */}
-          {canDelete && !replyOpen && (
-            <button
-              type="button"
-              className="pr-comment-delete-btn"
-              onClick={() => setConfirmDelete(true)}
-              disabled={deleting}
-              title={t('commentsPanel.deleteTitle')}
-            >
-              {deleting ? t('commentsPanel.deleting') : t('common.delete')}
-            </button>
-          )}
-        </div>
-      )}
-      {deleteError && (
-        <div className="pr-comment-delete-error" role="alert">
-          {t('commentsPanel.deleteFailed', { msg: deleteError })}
-          <button
-            type="button"
-            className="pr-comment-delete-error-dismiss"
-            onClick={() => setDeleteError(null)}
-            aria-label={t('commentsPanel.dismissErrorAria')}
-            title={t('commentsPanel.dismissErrorTitle')}
-          >
-            ✕
-          </button>
-        </div>
-      )}
-      {replyOpen && (
-        <CommentReplyEditor
-          prLocalId={pr.localId}
-          // 回复目标抽象（threadId）：GitLab=discussion id（reply 必需）；Bitbucket 空 / GitHub=remoteId → 回退 remoteId。
-          parentCommentId={comment.threadId ?? comment.remoteId}
-          onCancel={() => setReplyOpen(false)}
-          onPosted={() => setReplyOpen(false)}
-        />
-      )}
-      {comment.replies.length > 0 && (
-        // 满 MAX_REPLY_DEPTH 层后用 pr-comments-flat 取代 pr-comments-replies（不再缩进 / 左边框）→
-        // 更深回复拉平在该层缩进上；pr-comments-flat 据此给同层级相邻评论加横向分割线区分。
-        <ul
-          className={`pr-comments-list ${depth < MAX_REPLY_DEPTH ? 'pr-comments-replies' : 'pr-comments-flat'}`}
-        >
-          {comment.replies.map((r) => (
-            <CommentItem
-              key={r.remoteId}
-              comment={r}
-              pr={pr}
-              depth={depth + 1}
-              hardBreaks={hardBreaks}
-            />
-          ))}
-        </ul>
-      )}
-      {confirmDelete && (
-        <ConfirmModal
-          title={t('commentsPanel.deleteConfirmTitle')}
-          message={t('commentsPanel.deleteConfirmMessage')}
-          confirmLabel={t('common.delete')}
-          cancelLabel={t('common.cancel')}
-          danger
-          onConfirm={() => void handleDelete()}
-          onCancel={() => setConfirmDelete(false)}
-        />
-      )}
-    </li>
-  );
-}
-
-function formatRelativeTime(iso: string): string {
-  const t = Date.parse(iso);
-  if (Number.isNaN(t)) return iso;
-  const diffSec = Math.max(0, Math.round((Date.now() - t) / 1000));
-  if (diffSec < 60) return i18n.t('commentsPanel.justNow');
-  if (diffSec < 3600)
-    return i18n.t('commentsPanel.minutesAgo', { count: Math.round(diffSec / 60) });
-  if (diffSec < 86400)
-    return i18n.t('commentsPanel.hoursAgo', { count: Math.round(diffSec / 3600) });
-  if (diffSec < 86400 * 7)
-    return i18n.t('commentsPanel.daysAgo', { count: Math.round(diffSec / 86400) });
-  return new Date(t).toLocaleDateString();
-}
diff --git a/apps/desktop/src/renderer/src/i18n/locales/de-DE.json b/apps/desktop/src/renderer/src/i18n/locales/de-DE.json
index c9f574f..d14ebe3 100644
--- a/apps/desktop/src/renderer/src/i18n/locales/de-DE.json
+++ b/apps/desktop/src/renderer/src/i18n/locales/de-DE.json
@@ -1,4 +1,17 @@
 {
+  "activityPanel": {
+    "empty": "Noch keine Aktivität in diesem PR",
+    "loadError": "Aktivität konnte nicht geladen werden · {{title}}",
+    "loading": "Aktivität wird geladen…",
+    "mergeCommit": "Merge-Commit · {{parents}} Eltern",
+    "verb": {
+      "approved": "hat genehmigt",
+      "commented": "hat kommentiert",
+      "dismissed": "hat die Review verworfen",
+      "needsWork": "hat Änderungen angefordert",
+      "unapproved": "hat die Genehmigung zurückgezogen"
+    }
+  },
   "app": {
     "approveActionFailed": "Genehmigungsaktion fehlgeschlagen: {{msg}}",
     "loading": "Wird geladen…",
@@ -137,6 +150,15 @@
     "userQuestionAria": "Benutzerfrage",
     "waitingOutput": "(Warte auf PR-Agent-Ausgabe…)"
   },
+  "commentComposer": {
+    "cancelTitle": "Abbrechen (Esc)",
+    "emptyTitle": "Kommentar darf nicht leer sein",
+    "placeholder": "Kommentar schreiben…",
+    "send": "Kommentieren",
+    "sendTitle": "Senden (Cmd/Ctrl+Enter)",
+    "sending": "Wird gesendet…",
+    "textareaAria": "Editor für neuen Kommentar"
+  },
   "commentEditEditor": {
     "cancelTitle": "Abbrechen (Esc)",
     "emptyTitle": "Kommentar darf nicht leer sein",
@@ -453,6 +475,7 @@
     "mergeTitle": "Diesen PR in den Ziel-Branch mergen",
     "merging": "Wird gemergt…",
     "needsWork": "Nachbesserung nötig",
+    "newComment": "Kommentieren",
     "openInBrowser": "Im Browser öffnen",
     "openInBrowserTitle": "Die entfernte Seite des PR im Standardbrowser öffnen",
     "ownPrReason": "Sie können Ihren eigenen PR nicht reviewen",
@@ -461,6 +484,7 @@
     "showBlame": "Blame aktivieren (nur head-Seite)",
     "showWhitespace": "Leerzeichen anzeigen (Leerzeichen / Tab)",
     "sideBySide": "Nebeneinander",
+    "tabActivity": "Aktivität",
     "tabComments": "Kommentare",
     "tabCommits": "Commits",
     "tabDiff": "Änderungen",
@@ -529,6 +553,11 @@
     "needsWorkCount_one": "{{count}} Reviewer hat „Nachbesserung nötig“ markiert",
     "needsWorkCount_other": "{{count}} Reviewer haben „Nachbesserung nötig“ markiert"
   },
+  "prStatus": {
+    "approved": "Genehmigt",
+    "needsWork": "Änderungen nötig",
+    "pending": "Ausstehend"
+  },
   "publishReviewModal": {
     "allPublished": "Alle Entwürfe wurden auf den Remote geschrieben; die Kommentarliste wird sofort aktualisiert.",
     "countSummary": "{{total}} insgesamt, {{selected}} ausgewählt",
diff --git a/apps/desktop/src/renderer/src/i18n/locales/en-US.json b/apps/desktop/src/renderer/src/i18n/locales/en-US.json
index 218452e..de04d53 100644
--- a/apps/desktop/src/renderer/src/i18n/locales/en-US.json
+++ b/apps/desktop/src/renderer/src/i18n/locales/en-US.json
@@ -1,4 +1,17 @@
 {
+  "activityPanel": {
+    "empty": "No activity yet",
+    "loadError": "Failed to load activity · {{title}}",
+    "loading": "Loading activity…",
+    "mergeCommit": "Merge commit · {{parents}} parents",
+    "verb": {
+      "approved": "approved",
+      "commented": "commented",
+      "dismissed": "dismissed review",
+      "needsWork": "requested changes",
+      "unapproved": "withdrew approval"
+    }
+  },
   "app": {
     "approveActionFailed": "Approval action failed: {{msg}}",
     "loading": "Loading…",
@@ -137,6 +150,15 @@
     "userQuestionAria": "User question",
     "waitingOutput": "(Waiting for PR Agent output…)"
   },
+  "commentComposer": {
+    "cancelTitle": "Cancel (Esc)",
+    "emptyTitle": "Comment can't be empty",
+    "placeholder": "Write a comment…",
+    "send": "Comment",
+    "sendTitle": "Send (Cmd/Ctrl+Enter)",
+    "sending": "Sending…",
+    "textareaAria": "New comment editor"
+  },
   "commentEditEditor": {
     "cancelTitle": "Cancel (Esc)",
     "emptyTitle": "Comment can't be empty",
@@ -453,6 +475,7 @@
     "mergeTitle": "Merge this PR into the target branch",
     "merging": "Merging…",
     "needsWork": "Needs work",
+    "newComment": "Comment",
     "openInBrowser": "Open in browser",
     "openInBrowserTitle": "Open the PR's remote page in your default browser",
     "ownPrReason": "You can't review your own PR",
@@ -461,6 +484,7 @@
     "showBlame": "Enable blame (head side only)",
     "showWhitespace": "Show whitespace (spaces / tabs)",
     "sideBySide": "Side by side",
+    "tabActivity": "Activity",
     "tabComments": "Comments",
     "tabCommits": "Commits",
     "tabDiff": "Changes",
@@ -529,6 +553,11 @@
     "needsWorkCount_one": "{{count}} reviewer marked needs work",
     "needsWorkCount_other": "{{count}} reviewers marked needs work"
   },
+  "prStatus": {
+    "approved": "Approved",
+    "needsWork": "Needs work",
+    "pending": "Pending"
+  },
   "publishReviewModal": {
     "allPublished": "All drafts were written to the remote; the comment list will refresh immediately.",
     "countSummary": "{{total}} total, {{selected}} selected",
diff --git a/apps/desktop/src/renderer/src/i18n/locales/ja-JP.json b/apps/desktop/src/renderer/src/i18n/locales/ja-JP.json
index fb1e9b9..c9b565c 100644
--- a/apps/desktop/src/renderer/src/i18n/locales/ja-JP.json
+++ b/apps/desktop/src/renderer/src/i18n/locales/ja-JP.json
@@ -1,4 +1,17 @@
 {
+  "activityPanel": {
+    "empty": "この PR にはまだアクティビティがありません",
+    "loadError": "アクティビティの読み込みに失敗しました · {{title}}",
+    "loading": "アクティビティを読み込み中…",
+    "mergeCommit": "マージコミット · 親 {{parents}} 件",
+    "verb": {
+      "approved": "承認しました",
+      "commented": "コメントしました",
+      "dismissed": "レビューを取り消しました",
+      "needsWork": "変更をリクエストしました",
+      "unapproved": "承認を取り消しました"
+    }
+  },
   "app": {
     "approveActionFailed": "承認操作に失敗しました：{{msg}}",
     "loading": "読み込み中…",
@@ -137,6 +150,15 @@
     "userQuestionAria": "ユーザーの質問",
     "waitingOutput": "(PR Agent の出力を待機中…)"
   },
+  "commentComposer": {
+    "cancelTitle": "キャンセル (Esc)",
+    "emptyTitle": "コメントを空にはできません",
+    "placeholder": "コメントを入力…",
+    "send": "コメント",
+    "sendTitle": "送信 (Cmd/Ctrl+Enter)",
+    "sending": "送信中…",
+    "textareaAria": "新規コメントエディタ"
+  },
   "commentEditEditor": {
     "cancelTitle": "キャンセル (Esc)",
     "emptyTitle": "コメントを空にはできません",
@@ -440,6 +462,7 @@
     "mergeTitle": "この PR をターゲットブランチにマージします",
     "merging": "マージ中…",
     "needsWork": "要修正",
+    "newComment": "コメント",
     "openInBrowser": "ブラウザで開く",
     "openInBrowserTitle": "PR のリモートページを既定のブラウザで開きます",
     "ownPrReason": "自分の PR はレビューできません",
@@ -448,6 +471,7 @@
     "showBlame": "Blame を有効化（head 側のみ）",
     "showWhitespace": "空白文字を表示（スペース / Tab）",
     "sideBySide": "並べて表示",
+    "tabActivity": "アクティビティ",
     "tabComments": "コメント",
     "tabCommits": "コミット",
     "tabDiff": "変更",
@@ -514,6 +538,11 @@
     "mergeable": "マージ可能：すべてのマージ条件を満たしています",
     "needsWorkCount_other": "{{count}} 人のレビュアーが要修正とマークしました"
   },
+  "prStatus": {
+    "approved": "承認済み",
+    "needsWork": "要修正",
+    "pending": "保留中"
+  },
   "publishReviewModal": {
     "allPublished": "すべての下書きがリモートに書き込まれました。コメント一覧はすぐに更新されます。",
     "countSummary": "全 {{total}} 件中 {{selected}} 件を選択",
diff --git a/apps/desktop/src/renderer/src/i18n/locales/zh-CN.json b/apps/desktop/src/renderer/src/i18n/locales/zh-CN.json
index a7e3329..b8ee41f 100644
--- a/apps/desktop/src/renderer/src/i18n/locales/zh-CN.json
+++ b/apps/desktop/src/renderer/src/i18n/locales/zh-CN.json
@@ -1,4 +1,17 @@
 {
+  "activityPanel": {
+    "empty": "该 PR 暂无活动",
+    "loadError": "加载活动失败 · {{title}}",
+    "loading": "加载活动中…",
+    "mergeCommit": "合并提交 · {{parents}} 个父提交",
+    "verb": {
+      "approved": "批准",
+      "commented": "评论",
+      "dismissed": "驳回评审",
+      "needsWork": "要求修改",
+      "unapproved": "撤销批准"
+    }
+  },
   "app": {
     "approveActionFailed": "审批操作失败：{{msg}}",
     "loading": "加载中…",
@@ -137,6 +150,15 @@
     "userQuestionAria": "用户提问",
     "waitingOutput": "(等待 PR Agent 输出…)"
   },
+  "commentComposer": {
+    "cancelTitle": "取消 (Esc)",
+    "emptyTitle": "评论不能为空",
+    "placeholder": "写一条评论…",
+    "send": "评论",
+    "sendTitle": "发送 (Cmd/Ctrl+Enter)",
+    "sending": "发送中…",
+    "textareaAria": "新建评论编辑器"
+  },
   "commentEditEditor": {
     "cancelTitle": "取消 (Esc)",
     "emptyTitle": "评论不能为空",
@@ -440,6 +462,7 @@
     "mergeTitle": "合并此 PR 到目标分支",
     "merging": "合并中…",
     "needsWork": "需修改",
+    "newComment": "评论",
     "openInBrowser": "浏览器打开",
     "openInBrowserTitle": "在系统默认浏览器打开 PR 远端页面",
     "ownPrReason": "不能审批自己的 PR",
@@ -448,6 +471,7 @@
     "showBlame": "开启追溯显示（仅 head 侧）",
     "showWhitespace": "显示空白字符（空格 / Tab）",
     "sideBySide": "并排",
+    "tabActivity": "活动",
     "tabComments": "评论",
     "tabCommits": "提交",
     "tabDiff": "变更",
@@ -514,6 +538,11 @@
     "mergeable": "可合并：已满足所有合并条件",
     "needsWorkCount_other": "{{count}} 位 reviewer 标记 needs work"
   },
+  "prStatus": {
+    "approved": "已批准",
+    "needsWork": "要求修改",
+    "pending": "待评审"
+  },
   "publishReviewModal": {
     "allPublished": "所有草稿已写入远端，评论列表会立即刷新。",
     "countSummary": "共 {{total}} 条，已选 {{selected}}",
diff --git a/apps/desktop/src/renderer/src/styles/layout/main-pane.scss b/apps/desktop/src/renderer/src/styles/layout/main-pane.scss
index 5634228..b2e716f 100644
--- a/apps/desktop/src/renderer/src/styles/layout/main-pane.scss
+++ b/apps/desktop/src/renderer/src/styles/layout/main-pane.scss
@@ -493,6 +493,201 @@
   padding-top: $space-4;
   border-top: 1px solid $border-muted;
 }
+
+// 时间线模式的顶层评论：li 自身退掉卡片样式（卡片下移到 .pr-comment-card），标题行走 .pr-activity-item
+// 版式与其它事件统一；正文卡片整体缩进、挂在时间线轨右侧。
+.pr-comment-timeline.pr-comment-depth-0 {
+  padding: 0;
+  background: none;
+  border: none;
+  border-radius: 0;
+}
+.pr-comment-card {
+  // 缩进对齐到标题行的头像左缘（行左 padding + 图标 22 + gap）
+  margin-left: calc(22px + #{$space-3} * 2);
+  margin-top: $space-2;
+  padding: $space-4 $space-5;
+  background: $bg-elev;
+  border: 1px solid $border-default;
+  border-radius: $radius-md;
+}
+
+// ── 活动时间线：提交 / 评审决断事件行 + 评论行 ──
+// 所有条目（评论 / 提交 / 决断）首列都是同一位置的图标节点，正文在右；一条竖向虚线轨贯穿图标列、
+// 连接相邻条目，图标用面板底色遮住轨线形成「节点」效果。
+.pr-activity-list {
+  position: relative;
+
+  // 竖向虚线轨：居中于图标列（行左 padding $space-3 + 图标半宽 11px）。首尾各内缩一点，不超出首/末节点。
+  &::before {
+    content: '';
+    position: absolute;
+    top: $space-5;
+    bottom: $space-5;
+    left: calc(#{$space-3} + 11px);
+    border-left: 1px dashed $border-default;
+    z-index: 0;
+  }
+}
+.pr-activity-item {
+  display: flex;
+  align-items: center;
+  gap: $space-3;
+  padding: $space-2 $space-3;
+  // 与评论主体人文本同字号（body 默认 14px），作者展示不做差异化
+  font-size: $fs-lg;
+  color: $text-body;
+}
+.pr-activity-clickable {
+  cursor: pointer;
+  border-radius: $radius-sm;
+
+  &:hover {
+    background: $bg-hover;
+  }
+}
+.pr-activity-icon {
+  flex-shrink: 0;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 22px;
+  height: 22px;
+  color: $text-muted;
+  // 浮于虚线轨之上并用面板底色遮挡轨线 → 图标成为时间线节点
+  position: relative;
+  z-index: 1;
+  background: $bg-app;
+}
+// 决断语义色：approve 绿、needs-work 琥珀；unapproved / dismissed 维持中性 muted
+.pr-activity-icon-approved {
+  color: $color-approved;
+}
+.pr-activity-icon-needsWork {
+  color: $color-warning-bright;
+}
+.pr-activity-main {
+  flex: 1 1 auto;
+  min-width: 0;
+  display: flex;
+  align-items: center;
+  gap: $space-3;
+  overflow: hidden;
+}
+.pr-activity-commit-subject {
+  flex: 0 1 auto;
+  min-width: 0;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+.pr-activity-sha {
+  flex-shrink: 0;
+  font-family: $font-mono;
+  font-size: $fs-xs;
+  color: $text-muted;
+}
+.pr-activity-merge-tag {
+  flex-shrink: 0;
+  font-size: $fs-xs;
+  padding: 0 $space-2;
+  border-radius: $radius-sm;
+  background: $bg-hover;
+  color: $text-muted;
+}
+.pr-activity-actor {
+  flex-shrink: 0;
+  font-weight: 600;
+  color: $text-primary;
+}
+.pr-activity-verb {
+  color: $text-muted;
+}
+// reviewer 决断动词用带色 chip 突出：approve 绿、needs-work 琥珀、unapproved/dismissed 中性
+.pr-activity-chip {
+  flex-shrink: 0;
+  display: inline-flex;
+  align-items: center;
+  padding: 1px $space-3;
+  border-radius: $radius-pill;
+  // 与行内文本同字号（14px），比默认 chip 更突出
+  font-size: $fs-lg;
+  font-weight: 600;
+}
+.pr-activity-chip-approved {
+  background: rgba(22, 163, 74, 0.16);
+  color: $color-approved;
+}
+.pr-activity-chip-needsWork {
+  background: rgba(245, 158, 11, 0.18);
+  color: $color-warning-bright;
+}
+.pr-activity-chip-unapproved,
+.pr-activity-chip-dismissed {
+  background: $bg-hover;
+  color: $text-muted;
+}
+.pr-activity-time {
+  flex-shrink: 0;
+  margin-left: auto;
+  font-size: $fs-xs;
+}
+
+// 时间标签自定义 tooltip：原生 title 延迟长、且部分场景不弹（review 行），改用 data-tip + ::after，
+// 短延迟（120ms 显示、移开即隐），各时间标签行为一致、精确到秒。
+.time-tip {
+  position: relative;
+}
+.time-tip::after {
+  content: attr(data-tip);
+  position: absolute;
+  right: 0;
+  bottom: calc(100% + 4px);
+  z-index: 5;
+  padding: 2px $space-3;
+  white-space: nowrap;
+  font-size: $fs-sm;
+  color: $text-primary;
+  background: $bg-elev;
+  border: 1px solid $border-default;
+  border-radius: $radius-sm;
+  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
+  opacity: 0;
+  pointer-events: none;
+  transition: opacity 0.1s ease;
+}
+.time-tip:hover::after {
+  opacity: 1;
+  transition-delay: 0.12s;
+}
+
+// 新建评论编辑框：缩进对齐到标题行头像左缘，挂在时间线轨右侧（与评论卡片同一缩进）
+.pr-activity-compose-card {
+  margin-left: calc(22px + #{$space-3} * 2);
+}
+
+// 活动标签页右侧「评论」按钮：复用 diff 工具条按钮的轻量样式
+.pr-tab-action-btn {
+  display: inline-flex;
+  align-items: center;
+  gap: $space-2;
+  height: 22px;
+  box-sizing: border-box;
+  padding: 2px $space-4;
+  background: transparent;
+  border: 1px solid $border-default;
+  color: $text-muted;
+  cursor: pointer;
+  font-size: $fs-sm;
+  border-radius: $radius-sm;
+  white-space: nowrap;
+  flex-shrink: 0;
+
+  &:hover {
+    background: $bg-hover;
+    color: $text-primary;
+  }
+}
 .pr-comment-head {
   display: flex;
   align-items: center;
diff --git a/packages/ipc/src/pr.ts b/packages/ipc/src/pr.ts
index 24bf2ac..3540346 100644
--- a/packages/ipc/src/pr.ts
+++ b/packages/ipc/src/pr.ts
@@ -1,6 +1,7 @@
 import type {
   LocalPrStatus,
   PollResult,
+  PrActivityEvent,
   PrComment,
   PrCommit,
   ReviewDraft,
@@ -27,6 +28,14 @@ export interface PrChannels {
     request: { localId: string; parentCommentId: string; body: string };
     response: PrComment;
   };
+  /**
+   * 在 PR 上发一条 summary（顶层、不锚到文件）评论。成功后 main 端清评论缓存 + 广播
+   * comments:changed，活动 / 评论面板自动重拉，新评论出现在时间线顶部。
+   */
+  'comments:create': {
+    request: { localId: string; body: string };
+    response: PrComment;
+  };
   /**
    * 删除自己作者的远端评论。Bitbucket 要求带 version (乐观锁)，调用方从已有 PrComment
    * 拿；不一致 / 评论已有回复 / 自己不是作者都会失败 (Bitbucket 409/403)。成功后 main
@@ -110,6 +119,15 @@ export interface PrChannels {
     request: { localId: string };
     response: PrCommit[];
   };
+  /**
+   * 拉取 PR 上的评审决断活动事件（approve / needs-work / unapprove / dismiss），带时间戳。
+   * 活动时间线把它与评论 / 提交按时间归并。不缓存（量小，量级同 commits）；平台取不到历史
+   * 决断（如 GitLab CE 无审批）时返回 []，时间线只展示评论与提交。
+   */
+  'diff:listActivity': {
+    request: { localId: string };
+    response: PrActivityEvent[];
+  };
   /**
    * 本地 git rev-list 算 PR 引入的 commit 数 (base..head)。完全走本地 bare 镜像，
    * 不打远端；任一 sha 不在镜像 (尚未 sync 到本 PR 范围) → null。
diff --git a/packages/platform-bitbucket-server/src/adapter.ts b/packages/platform-bitbucket-server/src/adapter.ts
index 1149edc..25e85e2 100644
--- a/packages/platform-bitbucket-server/src/adapter.ts
+++ b/packages/platform-bitbucket-server/src/adapter.ts
@@ -5,6 +5,8 @@ import type {
   PlatformAdapter,
   PlatformCapabilities,
   PlatformUser,
+  PrActivityEvent,
+  PrActivityKind,
   PrComment,
   PrCommentAnchor,
   PrCommit,
@@ -87,7 +89,7 @@ interface BitbucketComment {
 interface BitbucketCommentAnchor {
   diffType?: 'EFFECTIVE' | 'COMMIT' | 'RANGE';
   // line / lineType 对文件级评论（挂在文件而非具体行）或孤儿 anchor（锚定行已不存在）
-  // 可能缺省 —— 标可选，mapBBAnchor 据此降级，避免读 undefined.toLowerCase 崩
+  // 可能缺省 —— 标可选，mapBitbucketAnchor 据此降级，避免读 undefined.toLowerCase 崩
   line?: number;
   lineType?: 'ADDED' | 'REMOVED' | 'CONTEXT';
   fileType?: 'FROM' | 'TO';
@@ -156,6 +158,7 @@ export class BitbucketServerAdapter implements PlatformAdapter {
       resolvableThreads: false,
       suggestions: false,
       reviewGrouping: false,
+      activityTimeline: true,
     };
   }
 
@@ -287,7 +290,7 @@ export class BitbucketServerAdapter implements PlatformAdapter {
       `/rest/api/1.0/projects/${repo.projectKey}/repos/${repo.repoSlug}/pull-requests/${prId}/comments`,
       { text: body, parent: { id: Number(parentCommentId) } },
     );
-    return mapBBComment(created);
+    return mapBitbucketComment(created);
   }
 
   async deleteComment(
@@ -324,7 +327,16 @@ export class BitbucketServerAdapter implements PlatformAdapter {
       // PUT 接口正常返回 JSON；走到这里只可能是上游 Bitbucket 配错回了 204
       throw new Error('editComment: Bitbucket 返回空响应，无法确认更新结果');
     }
-    return mapBBComment(updated);
+    return mapBitbucketComment(updated);
+  }
+
+  async publishSummaryComment(repo: RepoRef, prId: string, body: string): Promise<PrComment> {
+    // summary 评论：POST /pull-requests/{id}/comments，仅 text（不带 anchor / parent）
+    const created = await this.client.post<BitbucketComment>(
+      `/rest/api/1.0/projects/${repo.projectKey}/repos/${repo.repoSlug}/pull-requests/${prId}/comments`,
+      { text: body },
+    );
+    return mapBitbucketComment(created);
   }
 
   async publishInlineComment(
@@ -344,7 +356,7 @@ export class BitbucketServerAdapter implements PlatformAdapter {
       `/rest/api/1.0/projects/${repo.projectKey}/repos/${repo.repoSlug}/pull-requests/${prId}/comments`,
       { text: body, anchor: toBBAnchor(anchor) },
     );
-    return mapBBComment(created);
+    return mapBitbucketComment(created);
   }
 
   async getUserAvatar(
@@ -416,7 +428,7 @@ export class BitbucketServerAdapter implements PlatformAdapter {
     for await (const c of this.client.paginate<BitbucketCommit>(
       `/rest/api/1.0/projects/${repo.projectKey}/repos/${repo.repoSlug}/pull-requests/${prId}/commits`,
     )) {
-      out.push(mapBBCommit(c, this.baseUrl, repo));
+      out.push(mapBitbucketCommit(c, this.baseUrl, repo));
     }
     return out;
   }
@@ -439,13 +451,39 @@ export class BitbucketServerAdapter implements PlatformAdapter {
       const id = String(c.id);
       if (seen.has(id)) continue;
       seen.add(id);
-      out.push(mapBBComment(c, activity.commentAnchor));
+      out.push(mapBitbucketComment(c, activity.commentAnchor));
+    }
+    return out;
+  }
+
+  async listPullRequestActivity(repo: RepoRef, prId: string): Promise<PrActivityEvent[]> {
+    // 同 /activities 流里挑出决断类事件：APPROVED / UNAPPROVED / REVIEWED（= 标记 Needs Work）。
+    // 评论（COMMENTED）走 listPullRequestComments，这里只取评审决断。
+    const out: PrActivityEvent[] = [];
+    for await (const activity of this.client.paginate<BitbucketActivity>(
+      `/rest/api/1.0/projects/${repo.projectKey}/repos/${repo.repoSlug}/pull-requests/${prId}/activities`,
+    )) {
+      const kind: PrActivityKind | null =
+        activity.action === 'APPROVED'
+          ? 'approved'
+          : activity.action === 'UNAPPROVED'
+            ? 'unapproved'
+            : activity.action === 'REVIEWED'
+              ? 'needsWork'
+              : null;
+      if (!kind) continue;
+      out.push({
+        remoteId: String(activity.id),
+        kind,
+        actor: mapUser(activity.user),
+        createdAt: new Date(activity.createdDate).toISOString(),
+      });
     }
     return out;
   }
 }
 
-function mapBBCommit(c: BitbucketCommit, baseUrl: string, repo: RepoRef): PrCommit {
+function mapBitbucketCommit(c: BitbucketCommit, baseUrl: string, repo: RepoRef): PrCommit {
   // Bitbucket commit URL：/projects/<p>/repos/<r>/commits/<sha>
   const url = `${baseUrl}/projects/${repo.projectKey}/repos/${repo.repoSlug}/commits/${c.id}`;
   return {
@@ -470,21 +508,21 @@ function bitbucketCommitterToUser(c: { name: string; emailAddress?: string }): P
   return { name: c.name, displayName: c.name };
 }
 
-function mapBBComment(c: BitbucketComment, anchor?: BitbucketCommentAnchor): PrComment {
+function mapBitbucketComment(c: BitbucketComment, anchor?: BitbucketCommentAnchor): PrComment {
   return {
     remoteId: String(c.id),
     author: mapUser(c.author),
     body: c.text,
     createdAt: new Date(c.createdDate).toISOString(),
     updatedAt: new Date(c.updatedDate).toISOString(),
-    anchor: anchor ? mapBBAnchor(anchor) : null,
-    replies: (c.comments ?? []).map((r) => mapBBComment(r)),
+    anchor: anchor ? mapBitbucketAnchor(anchor) : null,
+    replies: (c.comments ?? []).map((r) => mapBitbucketComment(r)),
     // 透传 Bitbucket 乐观锁版本号 — DELETE / PUT 时调用方必须带回来，否则 409
     version: c.version,
   };
 }
 
-function mapBBAnchor(a: BitbucketCommentAnchor): PrCommentAnchor | null {
+function mapBitbucketAnchor(a: BitbucketCommentAnchor): PrCommentAnchor | null {
   // 无行号 = 文件级 / 孤儿 anchor，无法锚到具体行 → 返回 null，调用方退化成 summary 评论
   if (a.line == null) return null;
   return {
@@ -497,7 +535,7 @@ function mapBBAnchor(a: BitbucketCommentAnchor): PrCommentAnchor | null {
 }
 
 /**
- * 跨平台中性 anchor → Bitbucket REST 字段。mapBBAnchor 的反方向，发布 inline 评论时
+ * 跨平台中性 anchor → Bitbucket REST 字段。mapBitbucketAnchor 的反方向，发布 inline 评论时
  * 用。diffType 显式给 'EFFECTIVE' 让评论锚到"当前生效 diff"而不是某次具体 commit
  * —— PR 后续 push 新 commit 时评论仍跟着行走。
  */
diff --git a/packages/platform-github/src/adapter.ts b/packages/platform-github/src/adapter.ts
index 90d5fd3..cda6f19 100644
--- a/packages/platform-github/src/adapter.ts
+++ b/packages/platform-github/src/adapter.ts
@@ -6,6 +6,8 @@ import type {
   PlatformAdapter,
   PlatformCapabilities,
   PlatformUser,
+  PrActivityEvent,
+  PrActivityKind,
   PrComment,
   PrCommentAnchor,
   PrCommit,
@@ -179,6 +181,7 @@ export class GitHubAdapter implements PlatformAdapter {
       resolvableThreads: false,
       suggestions: false,
       reviewGrouping: false,
+      activityTimeline: true,
     };
   }
 
@@ -253,6 +256,35 @@ export class GitHubAdapter implements PlatformAdapter {
     return out.reverse();
   }
 
+  async listPullRequestActivity(repo: RepoRef, prId: string): Promise<PrActivityEvent[]> {
+    const reviews = await collect(
+      this.client.paginate<GhReview>(
+        `/repos/${repo.projectKey}/${repo.repoSlug}/pulls/${prId}/reviews`,
+      ),
+    );
+    const out: PrActivityEvent[] = [];
+    for (const r of reviews) {
+      // COMMENTED / PENDING 不是决断；submitted_at 缺失（草稿态）跳过
+      if (!r.user || !r.submitted_at) continue;
+      const kind: PrActivityKind | null =
+        r.state === 'APPROVED'
+          ? 'approved'
+          : r.state === 'CHANGES_REQUESTED'
+            ? 'needsWork'
+            : r.state === 'DISMISSED'
+              ? 'dismissed'
+              : null;
+      if (!kind) continue;
+      out.push({
+        remoteId: String(r.id),
+        kind,
+        actor: mapUser(r.user),
+        createdAt: r.submitted_at,
+      });
+    }
+    return out;
+  }
+
   async listPullRequestComments(repo: RepoRef, prId: string): Promise<PrComment[]> {
     const prefix = `/repos/${repo.projectKey}/${repo.repoSlug}`;
     const [issueComments, reviewComments] = await Promise.all([
@@ -303,6 +335,15 @@ export class GitHubAdapter implements PlatformAdapter {
     return this.client.getBinary(url);
   }
 
+  async publishSummaryComment(repo: RepoRef, prId: string, body: string): Promise<PrComment> {
+    // summary 评论 = issue 评论（无线程、无锚点）
+    const created = await this.client.post<GhIssueComment>(
+      `/repos/${repo.projectKey}/${repo.repoSlug}/issues/${prId}/comments`,
+      { body },
+    );
+    return mapIssueComment(created);
+  }
+
   async publishInlineComment(
     repo: RepoRef,
     prId: string,
diff --git a/packages/platform-gitlab/src/adapter.ts b/packages/platform-gitlab/src/adapter.ts
index 7ce54fd..48e3f11 100644
--- a/packages/platform-gitlab/src/adapter.ts
+++ b/packages/platform-gitlab/src/adapter.ts
@@ -6,6 +6,7 @@ import type {
   PlatformAdapter,
   PlatformCapabilities,
   PlatformUser,
+  PrActivityEvent,
   PrComment,
   PrCommentAnchor,
   PrCommit,
@@ -177,6 +178,8 @@ export class GitLabAdapter implements PlatformAdapter {
       resolvableThreads: false,
       suggestions: false,
       reviewGrouping: false,
+      // GitLab 无统一活动事件源（CE 无审批、审批系统 note 解析脆弱）→ PR 标签页退化为纯评论视图。
+      activityTimeline: false,
     };
   }
 
@@ -291,6 +294,13 @@ export class GitLabAdapter implements PlatformAdapter {
     return out;
   }
 
+  async listPullRequestActivity(_repo: RepoRef, _prId: string): Promise<PrActivityEvent[]> {
+    // 差异化设计：GitLab 不参与活动时间线（capabilities.activityTimeline=false，PR 标签页退化为纯
+    // 评论视图），故无需提供决断事件。GitLab 也没有统一活动事件源——CE 无审批、审批仅以脆弱的英文
+    // 系统 note 体现，与 Bitbucket /activities、GitHub /reviews 的可靠时间戳事件不对等——返回空。
+    return [];
+  }
+
   async getUserAvatar(
     _slug: string,
     avatarUrl?: string,
@@ -329,6 +339,15 @@ export class GitLabAdapter implements PlatformAdapter {
     return null;
   }
 
+  async publishSummaryComment(repo: RepoRef, prId: string, body: string): Promise<PrComment> {
+    // summary 评论 = 不带 position 的新 discussion（顶层 note）
+    const created = await this.client.post<GlDiscussion>(
+      `/projects/${projectId(repo)}/merge_requests/${prId}/discussions`,
+      { body },
+    );
+    return mapNote(created.notes[0]!, created.id, this.cachedUser?.name);
+  }
+
   async publishInlineComment(
     repo: RepoRef,
     prId: string,
diff --git a/packages/poller/tests/poller.test.ts b/packages/poller/tests/poller.test.ts
index 04eab0b..ac855fd 100644
--- a/packages/poller/tests/poller.test.ts
+++ b/packages/poller/tests/poller.test.ts
@@ -47,6 +47,7 @@ class FakeAdapter implements PlatformAdapter {
       resolvableThreads: false,
       suggestions: false,
       reviewGrouping: false,
+      activityTimeline: true,
     };
   }
   async ping() {
@@ -69,6 +70,9 @@ class FakeAdapter implements PlatformAdapter {
   async listPullRequestCommits(): Promise<never[]> {
     return [];
   }
+  async listPullRequestActivity(): Promise<never[]> {
+    return [];
+  }
   async getUserAvatar(): Promise<null> {
     return null;
   }
@@ -85,6 +89,9 @@ class FakeAdapter implements PlatformAdapter {
   async replyToComment(): Promise<never> {
     throw new Error('FakeAdapter.replyToComment 未实现（poller 测试不使用）');
   }
+  async publishSummaryComment(): Promise<never> {
+    throw new Error('FakeAdapter.publishSummaryComment 未实现（poller 测试不使用）');
+  }
   async publishInlineComment(): Promise<never> {
     throw new Error('FakeAdapter.publishInlineComment 未实现（poller 测试不使用）');
   }
@@ -253,6 +260,7 @@ describe('Poller.tick', () => {
         resolvableThreads: false,
         suggestions: false,
         reviewGrouping: false,
+        activityTimeline: true,
       }),
       async ping() {
         return { ok: true };
@@ -267,6 +275,9 @@ describe('Poller.tick', () => {
       async listPullRequestCommits() {
         return [];
       },
+      async listPullRequestActivity() {
+        return [];
+      },
       async getUserAvatar() {
         return null;
       },
@@ -277,6 +288,7 @@ describe('Poller.tick', () => {
       getAttachment: () => Promise.reject(new Error('unused')),
       mergePullRequest: () => Promise.reject(new Error('unused')),
       replyToComment: () => Promise.reject(new Error('unused')),
+      publishSummaryComment: () => Promise.reject(new Error('unused')),
       publishInlineComment: () => Promise.reject(new Error('unused')),
       deleteComment: () => Promise.reject(new Error('unused')),
       editComment: () => Promise.reject(new Error('unused')),
diff --git a/packages/shared/src/platform.ts b/packages/shared/src/platform.ts
index fd6b80e..4983418 100644
--- a/packages/shared/src/platform.ts
+++ b/packages/shared/src/platform.ts
@@ -184,6 +184,33 @@ export interface PrComment {
   nativeId?: string;
 }
 
+/**
+ * PR 评审决断事件的判定类型。`dismissed` = 决断被撤销/作废（GitHub DISMISSED），
+ * 与主动 `unapproved`（撤回赞成）语义相近但来源不同，保留区分供 UI 文案。
+ */
+export type PrActivityKind = 'approved' | 'needsWork' | 'unapproved' | 'dismissed';
+
+/**
+ * PR 活动时间线上的「评审决断」事件（带时间戳）。跨平台中性形状，由各 adapter 从原生活动流
+ * 映射：GitHub `/pulls/{n}/reviews`（state + submitted_at）；Bitbucket `/activities`
+ * （action=APPROVED/REVIEWED/UNAPPROVED + createdDate）；GitLab 系统 note（approved/
+ * unapproved，CE 无审批则取不到）。
+ *
+ * 仅承载评论 / 提交之外的「决断类」事件——评论走 {@link PrComment}、提交走 {@link PrCommit}，
+ * 渲染层把三路按时间归并成一条时间线。平台拿不到历史事件时该方法返回空数组。
+ */
+export interface PrActivityEvent {
+  /** 平台侧事件 id（去重 / React key 用） */
+  remoteId: string;
+  kind: PrActivityKind;
+  /** 触发该决断的用户 */
+  actor: PlatformUser;
+  /** ISO */
+  createdAt: string;
+  /** 决断附带正文（GitHub review body 可能带说明）；无则省略 */
+  body?: string;
+}
+
 /**
  * PR 的 diff 基准 sha（行内评论发布锚点用）。GitHub 用 `headSha` 作 commit_id；
  * GitLab 用三者拼 position；Bitbucket 不需要（忽略）。adapter 可按 prId 内部拉取，
@@ -233,6 +260,13 @@ export interface PlatformCapabilities {
   suggestions: boolean;
   /** 决断 + 行内评论是否可成组提交（pending review）；映射到本地草稿池→批量发布 */
   reviewGrouping: boolean;
+  /**
+   * 是否提供「带时间戳的评审决断活动事件流」（{@link PrActivityEvent}）以支撑活动时间线。
+   * GitHub（/reviews）/ Bitbucket（/activities）为 `true`：该 PR 标签页渲染评论 + 提交 + 决断
+   * 归并的「活动」时间线。GitLab 为 `false`：无统一活动事件源（CE 无审批、系统 note 解析脆弱），
+   * 标签页退化为纯「评论」视图（沿用原行为与文案），不混入提交 / 决断。
+   */
+  activityTimeline: boolean;
 }
 
 /**
@@ -308,6 +342,15 @@ export interface PlatformAdapter {
    */
   listPullRequestCommits(repo: RepoRef, prId: string): Promise<PrCommit[]>;
 
+  /**
+   * 列出 PR 上的「评审决断」活动事件（approve / needs-work / unapprove / dismiss），带时间戳。
+   * 供活动时间线与评论 / 提交归并展示。各平台映射来源见 {@link PrActivityEvent}。
+   *
+   * 顺序不约定（调用方按 createdAt 自行排序）。平台不支持取历史决断事件（如 GitLab CE 无审批）
+   * 时返回 `[]`，而非抛错——时间线据此优雅降级、只展示评论与提交。
+   */
+  listPullRequestActivity(repo: RepoRef, prId: string): Promise<PrActivityEvent[]>;
+
   /**
    * 拉用户头像图片。返回原始字节 + content-type，main 进程负责缓存与转 data URL；
    * renderer 不直接 fetch（无 token、无法跨 origin 取私有 Bitbucket 资源）。
@@ -370,6 +413,14 @@ export interface PlatformAdapter {
     body: string,
   ): Promise<PrComment>;
 
+  /**
+   * 在 PR 上发一条 summary（顶层、不锚到文件）评论。GitHub: POST /issues/{n}/comments；
+   * Bitbucket: POST /pull-requests/{id}/comments（不带 anchor / parent）；GitLab: POST
+   * /merge_requests/{iid}/discussions（不带 position）。返回新建评论（anchor=null），
+   * 调用方刷新 comments cache 让 UI 立即看到。
+   */
+  publishSummaryComment(repo: RepoRef, prId: string, body: string): Promise<PrComment>;
+
   /**
    * 在 PR diff 上发一条 inline 评论 (锚到具体文件 + 行号)。这是 M4 草稿发布闭环
    * 的 sink —— 本地 ReviewDraft 经此方法落到远端，成功后返回新评论 (含 remoteId