对话：顶栏快捷切换会话

src/lib/i18n/locales/en.ts

@@ -2753,6 +2753,7 @@ export const en = {
     header: {
       conversation: "Chat",
       titleAria: "Conversation title",
+      switchSession: "Switch session",
       pickCwd: "Click to choose a working directory",
       cwdUnset: "Working directory not set",
       cwdMissing: "Folder is gone",
@@ -2823,6 +2824,8 @@ export const en = {
       stop: "Stop",
       actions: "More actions",
       history: "Search history",
+      prevSession: "Previous session",
+      nextSession: "Next session",
       model: "Change model",
       newChat: "New chat",
       overview: "Shortcut overview",

src/lib/i18n/locales/zh.ts

@@ -2733,6 +2733,7 @@ export const zh = {
     header: {
       conversation: "对话",
       titleAria: "会话标题",
+      switchSession: "切换会话",
       pickCwd: "点击选择工作目录",
       cwdUnset: "未设置工作目录",
       cwdMissing: "目录已不存在",
@@ -2803,6 +2804,8 @@ export const zh = {
       stop: "停止",
       actions: "更多操作",
       history: "搜索历史会话",
+      prevSession: "上一条会话",
+      nextSession: "下一条会话",
       model: "换模型",
       newChat: "新建对话",
       overview: "快捷键一览",

src/pages/chat/ChatSessionHeader.tsx

@@ -1,15 +1,32 @@
 import { useEffect, useRef, useState } from 'react';
-import { Copy, FolderOpen, PanelLeftOpen, Settings2, ShieldAlert, Terminal } from 'lucide-react';
+import {
+  ChevronDown,
+  ChevronUp,
+  ChevronsUpDown,
+  Copy,
+  FolderOpen,
+  PanelLeftOpen,
+  Settings2,
+  ShieldAlert,
+  Terminal,
+} from 'lucide-react';
 import { ChromeActions } from '@/components/layout/ChromeActions';
 import { pageRhythm } from '@/components/layout/page-rhythm';
 import { copyTextToClipboard } from '@/components/shared/CopyTextButton';
 import { useI18n } from '@/components/shared/LanguageProvider';
 import { Button } from '@/components/ui/button';
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+} from '@/components/ui/dropdown-menu';
 import { Hint } from '@/components/ui/tooltip';
 import { Input } from '@/components/ui/input';
 import { useToast } from '@/components/ui/toast';
 import type { Conversation } from '@/lib/types';
 import { cn } from '@/lib/utils';
+import { sessionSwitchNeighbors } from './chat-session-switch';
 import { isKiroChatAgent } from './chat-kiro-model';
 import {
   chatConnectLabelKey,
@@ -32,8 +49,11 @@ export function ChatSessionHeader({
   active,
   railOpen,
   recordText,
+  sessions,
+  sendingConversationIds = [],
   onExpandRail,
   onRename,
+  onFocus,
   onOpenSettings,
   onPickWorkingDirectory,
   runtimeLocked = false,
@@ -44,8 +64,11 @@ export function ChatSessionHeader({
   active: Conversation | null;
   railOpen: boolean;
   recordText?: string;
+  sessions: readonly Conversation[];
+  sendingConversationIds?: readonly string[];
   onExpandRail: () => void;
   onRename: (next: string) => Promise<boolean>;
+  onFocus: (id: string) => void;
   onOpenSettings: () => void;
   onPickWorkingDirectory: () => void;
   runtimeLocked?: boolean;
@@ -114,7 +137,14 @@ export function ChatSessionHeader({
         </Button>
       )}
       <div className="min-w-0 flex-1">
-        {active && editing ? (
+        {!railOpen && sessions.length > 0 ? (
+          <ChatSessionSwitcher
+            sessions={sessions}
+            active={active}
+            sendingConversationIds={sendingConversationIds}
+            onFocus={onFocus}
+          />
+        ) : active && editing ? (
           <Input
             ref={inputRef}
             value={draftTitle}
@@ -311,3 +341,100 @@ export function ChatSessionHeader({
 function shortenId(id: string, max: number): string {
   return id.length <= max ? id : `${id.slice(0, max - 1)}…`;
 }
+
+function SendingDot({ sending }: { sending: boolean }) {
+  if (!sending) return null;
+  return (
+    <span aria-hidden className="inline-block h-1.5 w-1.5 shrink-0 rounded-full bg-accent" data-sending="" />
+  );
+}
+
+function ChatSessionSwitcher({
+  sessions,
+  active,
+  sendingConversationIds,
+  onFocus,
+}: {
+  sessions: readonly Conversation[];
+  active: Conversation | null;
+  sendingConversationIds: readonly string[];
+  onFocus: (id: string) => void;
+}) {
+  const { t } = useI18n();
+  const neighbors = sessionSwitchNeighbors(sessions, active?.id ?? null);
+  const title = active ? conversationTitle(t, active.title) : t('chat.header.conversation');
+  const cwdLabel = active ? cwdShortName(active.cwd, t) : t('chat.cwd.unset');
+  const sendingHere = Boolean(active && sendingConversationIds.includes(active.id));
+
+  return (
+    <div className="flex min-w-0 items-center gap-0.5" data-help="chat-session-switch">
+      <Button
+        type="button"
+        size="icon"
+        variant="ghost"
+        className="text-muted"
+        disabled={!neighbors.prevId}
+        title={t('chat.shortcuts.prevSession')}
+        aria-label={t('chat.shortcuts.prevSession')}
+        aria-keyshortcuts="Alt+ArrowUp"
+        onClick={() => {
+          if (neighbors.prevId) onFocus(neighbors.prevId);
+        }}
+      >
+        <ChevronUp className="h-4 w-4" />
+      </Button>
+      <DropdownMenu modal={false}>
+        <DropdownMenuTrigger asChild>
+          <Button
+            type="button"
+            size="sm"
+            variant="ghost"
+            className="min-w-0 max-w-xs justify-start px-1.5"
+            aria-label={t('chat.header.switchSession')}
+          >
+            <SendingDot sending={sendingHere} />
+            <span className="min-w-0 truncate font-semibold text-primary">{title}</span>
+            <span className="min-w-0 truncate text-meta font-normal text-muted">{cwdLabel}</span>
+            <ChevronsUpDown className="h-3.5 w-3.5 shrink-0 text-muted" aria-hidden />
+          </Button>
+        </DropdownMenuTrigger>
+        <DropdownMenuContent align="start" className="max-h-72 min-w-[16rem] overflow-y-auto">
+          {sessions.map((session) => {
+            const selected = active?.id === session.id;
+            const sending = sendingConversationIds.includes(session.id);
+            return (
+              <DropdownMenuItem
+                key={session.id}
+                className={cn('items-start', selected && 'font-medium')}
+                onSelect={() => onFocus(session.id)}
+              >
+                <SendingDot sending={sending} />
+                <span className="min-w-0 flex-1">
+                  <span className="block truncate">{conversationTitle(t, session.title)}</span>
+                  <span className="block truncate text-meta text-muted">
+                    {cwdShortName(session.cwd, t)}
+                  </span>
+                </span>
+              </DropdownMenuItem>
+            );
+          })}
+        </DropdownMenuContent>
+      </DropdownMenu>
+      <Button
+        type="button"
+        size="icon"
+        variant="ghost"
+        className="text-muted"
+        disabled={!neighbors.nextId}
+        title={t('chat.shortcuts.nextSession')}
+        aria-label={t('chat.shortcuts.nextSession')}
+        aria-keyshortcuts="Alt+ArrowDown"
+        onClick={() => {
+          if (neighbors.nextId) onFocus(neighbors.nextId);
+        }}
+      >
+        <ChevronDown className="h-4 w-4" />
+      </Button>
+    </div>
+  );
+}

src/pages/chat/chat-session-switch.test.ts

@@ -0,0 +1,145 @@
+import { createElement, type ReactElement } from 'react';
+import { renderToStaticMarkup } from 'react-dom/server';
+import { describe, expect, it, vi } from 'vitest';
+import { TooltipProvider } from '@/components/ui/tooltip';
+import type { Conversation } from '@/lib/types';
+import { ChatSessionHeader } from './ChatSessionHeader';
+import {
+  adjacentSessionId,
+  chatSessionSwitchShortcutAction,
+  sessionSwitchNeighbors,
+} from './chat-session-switch';
+
+vi.mock('@/components/shared/LanguageProvider', async () => {
+  const { createTranslator } = await import('@/lib/i18n');
+  const t = createTranslator('zh');
+  return {
+    useI18n: () => ({ lang: 'zh', setLanguage: () => undefined, t }),
+  };
+});
+
+vi.mock('@/components/ui/toast', () => ({
+  useToast: () => ({ toast: () => undefined }),
+}));
+
+vi.mock('@/components/layout/ChromeActions', () => ({
+  ChromeActions: () => null,
+}));
+
+const sessions = [{ id: 'a' }, { id: 'b' }, { id: 'c' }];
+
+describe('adjacentSessionId', () => {
+  it('returns null for an empty list', () => {
+    expect(adjacentSessionId([], 'a', 'next')).toBeNull();
+    expect(adjacentSessionId([], null, 'prev')).toBeNull();
+  });
+
+  it('cannot switch a single-item list that is already focused', () => {
+    expect(adjacentSessionId([{ id: 'a' }], 'a', 'next')).toBeNull();
+    expect(adjacentSessionId([{ id: 'a' }], 'a', 'prev')).toBeNull();
+  });
+
+  it('focuses the only session when the current id is missing', () => {
+    expect(adjacentSessionId([{ id: 'a' }], null, 'next')).toBe('a');
+    expect(adjacentSessionId([{ id: 'a' }], 'gone', 'prev')).toBe('a');
+  });
+
+  it('walks the flat list and wraps at both ends', () => {
+    expect(adjacentSessionId(sessions, 'a', 'next')).toBe('b');
+    expect(adjacentSessionId(sessions, 'b', 'next')).toBe('c');
+    expect(adjacentSessionId(sessions, 'c', 'next')).toBe('a');
+    expect(adjacentSessionId(sessions, 'a', 'prev')).toBe('c');
+    expect(adjacentSessionId(sessions, 'b', 'prev')).toBe('a');
+    expect(adjacentSessionId(sessions, 'c', 'prev')).toBe('b');
+  });
+
+  it('lands on the first or last session when the current id is not in the list', () => {
+    expect(adjacentSessionId(sessions, null, 'next')).toBe('a');
+    expect(adjacentSessionId(sessions, 'gone', 'prev')).toBe('c');
+  });
+});
+
+describe('sessionSwitchNeighbors', () => {
+  it('exposes both wrapped neighbors', () => {
+    expect(sessionSwitchNeighbors(sessions, 'b')).toEqual({ prevId: 'a', nextId: 'c' });
+    expect(sessionSwitchNeighbors(sessions, 'a')).toEqual({ prevId: 'c', nextId: 'b' });
+    expect(sessionSwitchNeighbors([{ id: 'a' }], 'a')).toEqual({ prevId: null, nextId: null });
+  });
+});
+
+describe('chatSessionSwitchShortcutAction', () => {
+  const base = {
+    key: '',
+    altKey: true,
+    metaKey: false,
+    ctrlKey: false,
+    shiftKey: false,
+    overlayOpen: false,
+  };
+
+  it('maps Alt+ArrowUp / Alt+ArrowDown', () => {
+    expect(chatSessionSwitchShortcutAction({ ...base, key: 'ArrowUp' })).toBe('prev');
+    expect(chatSessionSwitchShortcutAction({ ...base, key: 'ArrowDown' })).toBe('next');
+    expect(
+      chatSessionSwitchShortcutAction({ ...base, key: 'Unidentified', code: 'ArrowUp' }),
+    ).toBe('prev');
+  });
+
+  it('ignores chords that already belong to Chat', () => {
+    expect(chatSessionSwitchShortcutAction({ ...base, key: 'k', ctrlKey: true, altKey: false })).toBeNull();
+    expect(chatSessionSwitchShortcutAction({ ...base, key: 'n', ctrlKey: true, altKey: false })).toBeNull();
+    expect(chatSessionSwitchShortcutAction({ ...base, key: 'Enter', altKey: false })).toBeNull();
+    expect(chatSessionSwitchShortcutAction({ ...base, key: 'Escape', altKey: false })).toBeNull();
+    expect(chatSessionSwitchShortcutAction({ ...base, key: '/', altKey: false })).toBeNull();
+    expect(chatSessionSwitchShortcutAction({ ...base, key: 'ArrowUp', altKey: false })).toBeNull();
+    expect(chatSessionSwitchShortcutAction({ ...base, key: 'ArrowUp', ctrlKey: true })).toBeNull();
+    expect(chatSessionSwitchShortcutAction({ ...base, key: 'ArrowUp', overlayOpen: true })).toBeNull();
+  });
+});
+
+function conv(partial?: Partial<Conversation>): Conversation {
+  return {
+    id: 'a',
+    title: '修登录',
+    agentIds: ['claude'],
+    cwd: 'D:\\work\\agenthub',
+    allowDangerous: false,
+    createdAt: '2026-09-20T00:00:00.000Z',
+    updatedAt: '2026-09-20T00:00:00.000Z',
+    ...partial,
+  };
+}
+
+function header(partial?: Partial<Parameters<typeof ChatSessionHeader>[0]>): ReactElement {
+  const active = conv();
+  return createElement(ChatSessionHeader, {
+    active,
+    railOpen: false,
+    sessions: [active, conv({ id: 'b', title: '下一场', cwd: 'D:\\work\\other' })],
+    sendingConversationIds: ['a'],
+    onExpandRail: () => undefined,
+    onRename: async () => true,
+    onFocus: () => undefined,
+    onOpenSettings: () => undefined,
+    onPickWorkingDirectory: () => undefined,
+    ...partial,
+  });
+}
+
+describe('collapsed session switcher', () => {
+  it('shows the current title, working-directory short name, and a sending dot', () => {
+    const html = renderToStaticMarkup(createElement(TooltipProvider, null, header()));
+    expect(html).toContain('data-help="chat-session-switch"');
+    expect(html).toContain('修登录');
+    expect(html).toContain('agenthub');
+    expect(html).toContain('data-sending=""');
+    expect(html).toContain('上一条会话');
+    expect(html).toContain('下一条会话');
+  });
+
+  it('keeps the rename title when the history rail is open', () => {
+    const html = renderToStaticMarkup(createElement(TooltipProvider, null, header({ railOpen: true })));
+    expect(html).not.toContain('data-help="chat-session-switch"');
+    expect(html).toContain('修登录');
+  });
+});