fix(agent-browser): restore bounded presentation lifecycle

src/pages/Chat/CodingConversationHeader.tsx

@@ -3,6 +3,8 @@ import { createPortal } from 'react-dom';
 import {
   LoaderCircle,
   Pencil,
+  PanelRightClose,
+  PanelRightOpen,
   RotateCcw,
   Square,
 } from 'lucide-react';
@@ -55,12 +57,18 @@ export function CodingConversationHeader({
   onRename,
   onAbort,
   onRecover,
+  browserOpen = false,
+  browserAvailable = false,
+  onToggleBrowser,
 }: {
   conversation: CodingConversationMetadata | null;
   snapshot: ConversationSnapshot | null;
   onRename(title: string): Promise<void>;
   onAbort(): Promise<void>;
   onRecover(): Promise<void>;
+  browserOpen?: boolean;
+  browserAvailable?: boolean;
+  onToggleBrowser?(): void;
 }) {
   const sidebarCollapsed = useSettingsStore((state) => state.sidebarCollapsed);
   const [busyAction, setBusyAction] = useState<string | null>(null);
@@ -121,6 +129,23 @@ export function CodingConversationHeader({
         </button>
       </div>
 
+      {onToggleBrowser ? (
+        <Button
+          type="button"
+          variant="ghost"
+          className={iconButtonClass}
+          disabled={!browserAvailable}
+          aria-label={browserOpen ? '关闭开发浏览器' : '打开开发浏览器'}
+          aria-pressed={browserOpen}
+          title={browserOpen ? '关闭开发浏览器' : '打开开发浏览器'}
+          onClick={onToggleBrowser}
+        >
+          {browserOpen
+            ? <PanelRightClose className="h-4 w-4" aria-hidden="true" />
+            : <PanelRightOpen className="h-4 w-4" aria-hidden="true" />}
+        </Button>
+      ) : null}
+
       {running && runStatus !== 'aborting' && (
         <Button
           type="button"