feat: 对话框上方集成专家选择器，支持实时选择与系统提示词注入

- 新建 ExpertSelector 组件，加载时查询 session 选中状态，失败降级显示无专家

- 下拉面板含无专家/专家列表/管理专家入口，乐观更新+失败回滚保证一致性

- ChatContainer 在 MessageList 与 MessageInput 之间渲染 ExpertSelector

- MessageInput 接收 selectedExpert，选中时 placeholder 显示以专家身份对话

- App.tsx 传递 sessionId/onOpenSettings 给 ChatContainer，支持从对话框直达专家设置

- App.tsx 同时包含 subagent 导航 command 发送的连带修改

web/src/App.tsx

@@ -166,6 +166,7 @@ function App() {
   })
 
   const [configPageOpen, setConfigPageOpen] = useState(false)
+  const [configInitialTab, setConfigInitialTab] = useState<'providers' | 'experts'>('providers')
 
   const handleSaveConnection = useCallback((host: string, port: number) => {
     setGatewaySettings({ host, port })
@@ -355,8 +356,18 @@ function App() {
   )
 
   const handleExitSubAgentView = useCallback(() => {
-    exitSubAgentView()
+    const command = exitSubAgentView()
-  }, [exitSubAgentView])
+    if (command) {
+      sendMessage({ type: 'command', payload: JSON.stringify(command) })
+    }
+  }, [exitSubAgentView, sendMessage])
+
+  const handleNavigateToSubAgentLevel = useCallback((index: number) => {
+    const command = navigateToSubAgentLevel(index)
+    if (command) {
+      sendMessage({ type: 'command', payload: JSON.stringify(command) })
+    }
+  }, [navigateToSubAgentLevel, sendMessage])
 
   // 切换到定时任务 tab 时自动获取列表
   useEffect(() => {
@@ -567,7 +578,10 @@ function App() {
             <Brain className="h-4 w-4" />
           </button>
           <button
-            onClick={() => setConfigPageOpen(true)}
+            onClick={() => {
+              setConfigInitialTab('providers')
+              setConfigPageOpen(true)
+            }}
             className="flex h-8 w-8 items-center justify-center rounded-lg text-[var(--text-muted)] hover:text-[var(--accent-cyan)] hover:bg-[var(--overlay-hover)] transition-all"
             title="系统配置"
             aria-label="System config"
@@ -726,7 +740,7 @@ function App() {
               </button>
               {/* Breadcrumb: 主会话 */}
               <button
-                onClick={() => navigateToSubAgentLevel(-1)}
+                onClick={() => handleNavigateToSubAgentLevel(-1)}
                 className="flex items-center gap-1 text-sm text-[var(--text-muted)] hover:text-[var(--accent-cyan)] transition-colors shrink-0"
                 title="返回主会话"
               >
@@ -762,7 +776,7 @@ function App() {
                       </div>
                     ) : (
                       <button
-                        onClick={() => navigateToSubAgentLevel(idx)}
+                        onClick={() => handleNavigateToSubAgentLevel(idx)}
                         className="flex items-center gap-2 text-sm text-[var(--text-muted)] hover:text-[var(--accent-cyan)] transition-colors min-w-0"
                       >
                         <span className="truncate">{level.description}</span>
@@ -793,6 +807,11 @@ function App() {
               showThinking={showThinking}
               viewKey={viewKey}
               highlightedMessageId={highlightedMessageId}
+              sessionId={sessionId}
+              onOpenSettings={() => {
+                setConfigInitialTab('experts')
+                setConfigPageOpen(true)
+              }}
             />
           </div>
         </div>
@@ -881,7 +900,11 @@ function App() {
 
       {/* 系统配置页面 */}
       {configPageOpen && (
-        <ConfigPage onClose={() => setConfigPageOpen(false)} onSaveConnection={handleSaveConnection} />
+        <ConfigPage
+          onClose={() => setConfigPageOpen(false)}
+          onSaveConnection={handleSaveConnection}
+          initialTab={configInitialTab}
+        />
       )}
     </div>
   )

web/src/components/Chat/ChatContainer.tsx

@@ -1,5 +1,7 @@
+import { useState } from 'react'
 import { MessageList } from './MessageList'
 import { MessageInput } from './MessageInput'
+import { ExpertSelector } from './ExpertSelector'
 import type { ChatMessage, Attachment } from '../../types/protocol'
 
 interface ChatContainerProps {
@@ -15,6 +17,10 @@ interface ChatContainerProps {
   viewKey?: string
   /** 高亮的消息 ID */
   highlightedMessageId?: string | null
+  /** 当前 session ID，用于专家选择 */
+  sessionId?: string | null
+  /** 打开设置页（用于专家管理入口） */
+  onOpenSettings?: () => void
 }
 
 export function ChatContainer({
@@ -28,12 +34,21 @@ export function ChatContainer({
   showThinking = true,
   viewKey,
   highlightedMessageId,
+  sessionId,
+  onOpenSettings,
 }: ChatContainerProps) {
+  const [selectedExpert, setSelectedExpert] = useState<{ name: string; description: string } | null>(null)
+
   return (
     <div className="flex h-full flex-col relative">
       <div className="flex-1 overflow-hidden relative">
         <MessageList messages={messages} onNavigateToSubAgent={onNavigateToSubAgent} showThinking={showThinking} viewKey={viewKey} highlightedMessageId={highlightedMessageId} />
       </div>
+      <ExpertSelector
+        sessionId={sessionId ?? null}
+        onManageExperts={onOpenSettings}
+        onSelectionChange={setSelectedExpert}
+      />
       <MessageInput
         onSend={onSendMessage}
         onStop={onStop}
@@ -41,6 +56,7 @@ export function ChatContainer({
         isLoading={isLoading}
         isReadOnly={isReadOnly}
         channelName={channelName}
+        selectedExpert={selectedExpert}
       />
     </div>
   )

web/src/components/Chat/ExpertSelector.tsx

@@ -0,0 +1,247 @@
+import { useState, useEffect, useRef, useCallback } from 'react'
+import { UserCheck, ChevronDown, Loader2, Settings, Check } from 'lucide-react'
+import { getSelectedExpert, selectExpert } from '../Settings/ConfigPage'
+
+interface ExpertItem {
+  name: string
+  description: string
+  source: string
+  path?: string
+  body?: string
+  disabled_in_scopes: string[]
+}
+
+interface SelectedExpert {
+  name: string
+  description: string
+}
+
+interface ExpertSelectorProps {
+  sessionId: string | null
+  onManageExperts?: () => void
+  onSelectionChange?: (expert: SelectedExpert | null) => void
+}
+
+export function ExpertSelector({ sessionId, onManageExperts, onSelectionChange }: ExpertSelectorProps) {
+  const [selectedExpert, setSelectedExpert] = useState<SelectedExpert | null>(null)
+  const [expertList, setExpertList] = useState<ExpertItem[]>([])
+  const [open, setOpen] = useState(false)
+  const [loading, setLoading] = useState(false)
+  const [listLoading, setListLoading] = useState(false)
+  const [error, setError] = useState<string | null>(null)
+
+  const containerRef = useRef<HTMLDivElement>(null)
+  const listFetchedRef = useRef(false)
+
+  // Load current selection whenever sessionId changes
+  useEffect(() => {
+    if (!sessionId) {
+      setSelectedExpert(null)
+      onSelectionChange?.(null)
+      return
+    }
+    let cancelled = false
+    setLoading(true)
+    setError(null)
+    getSelectedExpert(sessionId)
+      .then(data => {
+        if (cancelled) return
+        if (data?.expert) {
+          setSelectedExpert({ name: data.expert.name, description: data.expert.description })
+          onSelectionChange?.({ name: data.expert.name, description: data.expert.description })
+        } else {
+          setSelectedExpert(null)
+          onSelectionChange?.(null)
+        }
+      })
+      .catch(() => {
+        if (cancelled) return
+        // Silent fail: default to no expert
+        setSelectedExpert(null)
+        onSelectionChange?.(null)
+      })
+      .finally(() => {
+        if (!cancelled) setLoading(false)
+      })
+    return () => { cancelled = true }
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [sessionId])
+
+  // Click outside to close dropdown
+  useEffect(() => {
+    if (!open) return
+    const handler = (e: MouseEvent) => {
+      if (containerRef.current && !containerRef.current.contains(e.target as Node)) {
+        setOpen(false)
+      }
+    }
+    document.addEventListener('mousedown', handler)
+    return () => document.removeEventListener('mousedown', handler)
+  }, [open])
+
+  const fetchExpertList = useCallback(async () => {
+    setListLoading(true)
+    try {
+      const resp = await fetch('/api/experts')
+      if (resp.ok) {
+        const data = await resp.json()
+        // Only show enabled experts (disabled_in_scopes.length === 0)
+        const enabled = (data.experts ?? []).filter(
+          (e: ExpertItem) => e.disabled_in_scopes.length === 0
+        )
+        setExpertList(enabled)
+      }
+    } catch { /* ignore */ }
+    finally { setListLoading(false) }
+  }, [])
+
+  const handleToggleOpen = () => {
+    const next = !open
+    setOpen(next)
+    if (next && !listFetchedRef.current) {
+      listFetchedRef.current = true
+      fetchExpertList()
+    }
+  }
+
+  const handleSelect = async (expert: SelectedExpert | null) => {
+    if (!sessionId) return
+    // Optimistic update
+    const prev = selectedExpert
+    setSelectedExpert(expert)
+    onSelectionChange?.(expert)
+    setOpen(false)
+    try {
+      const result = await selectExpert(sessionId, expert?.name ?? null)
+      if (!result.success) {
+        // Revert
+        setSelectedExpert(prev)
+        onSelectionChange?.(prev)
+        setError(result.error || '切换专家失败')
+        setTimeout(() => setError(null), 3000)
+      }
+    } catch {
+      setSelectedExpert(prev)
+      onSelectionChange?.(prev)
+      setError('网络错误，切换专家失败')
+      setTimeout(() => setError(null), 3000)
+    }
+  }
+
+  const handleManage = () => {
+    setOpen(false)
+    onManageExperts?.()
+  }
+
+  // If sessionId is null, render nothing
+  if (!sessionId) return null
+
+  return (
+    <div ref={containerRef} className="relative shrink-0 px-4 pt-2 pb-0">
+      <div className="max-w-5xl mx-auto flex items-center gap-2">
+        <button
+          onClick={handleToggleOpen}
+          disabled={loading}
+          className="group inline-flex items-center gap-1.5 px-2.5 py-1 rounded-lg border border-[var(--border-color)] bg-[var(--bg-tertiary)]/60 hover:border-[var(--accent-cyan)]/40 hover:bg-[var(--bg-tertiary)] transition-colors text-xs disabled:opacity-50"
+          title={selectedExpert ? `${selectedExpert.name}: ${selectedExpert.description}` : '未选中专家'}
+        >
+          {loading ? (
+            <Loader2 className="h-3.5 w-3.5 animate-spin text-[var(--text-muted)]" />
+          ) : (
+            <UserCheck
+              className={`h-3.5 w-3.5 ${selectedExpert ? 'text-[var(--accent-cyan)]' : 'text-[var(--text-muted)]'}`}
+            />
+          )}
+          {selectedExpert ? (
+            <span className="flex items-center gap-1 min-w-0">
+              <span className="text-[var(--text-primary)] font-medium truncate max-w-[120px]">
+                {selectedExpert.name}
+              </span>
+              <span className="text-[var(--text-muted)] truncate max-w-[180px]">
+                {selectedExpert.description}
+              </span>
+            </span>
+          ) : (
+            <span className="text-[var(--text-muted)]">无专家</span>
+          )}
+          <ChevronDown
+            className={`h-3 w-3 text-[var(--text-muted)] transition-transform ${open ? 'rotate-180' : ''}`}
+          />
+        </button>
+        {error && (
+          <span className="text-xs text-red-400 truncate">{error}</span>
+        )}
+      </div>
+
+      {open && (
+        <div
+          className="absolute z-30 mt-1 w-72 max-w-[90vw] rounded-xl border border-[var(--border-color)] bg-[var(--bg-secondary)] shadow-2xl backdrop-blur-md overflow-hidden"
+          style={{ left: 'max(1rem, calc(50% - 18rem))' }}
+        >
+          {listLoading && expertList.length === 0 ? (
+            <div className="flex items-center gap-2 px-3 py-3 text-xs text-[var(--text-muted)]">
+              <Loader2 className="h-3.5 w-3.5 animate-spin" /> 加载中...
+            </div>
+          ) : (
+            <>
+              {/* 无专家 option */}
+              <button
+                onClick={() => handleSelect(null)}
+                className="w-full flex items-center gap-2 px-3 py-2 text-left text-sm hover:bg-[var(--bg-hover)] transition-colors"
+              >
+                <UserCheck className="h-4 w-4 text-[var(--text-muted)] shrink-0" />
+                <span className="text-[var(--text-primary)]">无专家</span>
+                {!selectedExpert && (
+                  <Check className="h-3.5 w-3.5 text-[var(--accent-cyan)] ml-auto" />
+                )}
+              </button>
+              {expertList.length > 0 && (
+                <div className="border-t border-[var(--border-color)]">
+                  {expertList.map(expert => {
+                    const isSelected = selectedExpert?.name === expert.name
+                    return (
+                      <button
+                        key={expert.name}
+                        onClick={() => handleSelect({ name: expert.name, description: expert.description })}
+                        className="w-full flex items-start gap-2 px-3 py-2 text-left hover:bg-[var(--bg-hover)] transition-colors"
+                      >
+                        <UserCheck
+                          className={`h-4 w-4 shrink-0 mt-0.5 ${isSelected ? 'text-[var(--accent-cyan)]' : 'text-[var(--text-muted)]'}`}
+                        />
+                        <div className="min-w-0 flex-1">
+                          <div className="flex items-center gap-1.5">
+                            <span className="text-sm font-medium text-[var(--text-primary)] truncate">
+                              {expert.name}
+                            </span>
+                            <span className="text-[9px] px-1 py-0.5 rounded bg-[var(--bg-tertiary)] text-[var(--text-muted)] uppercase tracking-wider shrink-0">
+                              {expert.source}
+                            </span>
+                            {isSelected && (
+                              <Check className="h-3.5 w-3.5 text-[var(--accent-cyan)] ml-auto shrink-0" />
+                            )}
+                          </div>
+                          <p className="text-xs text-[var(--text-muted)] truncate mt-0.5">
+                            {expert.description}
+                          </p>
+                        </div>
+                      </button>
+                    )
+                  })}
+                </div>
+              )}
+              <div className="border-t border-[var(--border-color)]">
+                <button
+                  onClick={handleManage}
+                  className="w-full flex items-center gap-2 px-3 py-2 text-left text-sm text-[var(--text-secondary)] hover:text-[var(--accent-cyan)] hover:bg-[var(--bg-hover)] transition-colors"
+                >
+                  <Settings className="h-4 w-4" />
+                  <span>管理专家...</span>
+                </button>
+              </div>
+            </>
+          )}
+        </div>
+      )}
+    </div>
+  )
+}

web/src/components/Chat/MessageInput.tsx

@@ -12,6 +12,7 @@ interface MessageInputProps {
   placeholder?: string
   isReadOnly?: boolean
   channelName?: string
+  selectedExpert?: { name: string; description: string } | null
 }
 
 interface FileAttachment {
@@ -33,10 +34,13 @@ export function MessageInput({
   onStop,
   disabled = false,
   isLoading = false,
-  placeholder = '输入消息...按 / 查看命令',
+  placeholder,
   isReadOnly = false,
   channelName,
+  selectedExpert,
 }: MessageInputProps) {
+  const effectivePlaceholder = placeholder
+    ?? (selectedExpert ? `以 ${selectedExpert.name} 专家身份对话...` : '输入消息...按 / 查看命令')
   const [content, setContent] = useState('')
   const [attachments, setAttachments] = useState<FileAttachment[]>([])
   const [isDragging, setIsDragging] = useState(false)
@@ -360,7 +364,7 @@ export function MessageInput({
               onChange={(e) => setContent(e.target.value)}
               onKeyDown={handleKeyDown}
               onPaste={handlePaste}
-              placeholder={placeholder}
+              placeholder={effectivePlaceholder}
               disabled={disabled}
               rows={1}
               className="w-full resize-none rounded-xl border border-[var(--border-color)] bg-[var(--bg-tertiary)] px-4 py-3 pr-12 text-sm text-[var(--text-primary)] placeholder:text-[var(--text-muted)] focus:border-[var(--accent-cyan)]/50 focus:outline-none focus:ring-1 focus:ring-[var(--focus-ring)] disabled:opacity-50 transition-all self-center scrollbar-hide"