修复活跃的对话中会话在关闭会话tab后连接被自动回收了

src/hooks/use-connection-lifecycle.ts

@@ -266,9 +266,14 @@ export function useConnectionLifecycle({
 
   // Clean up on unmount (e.g. tab closed): disconnect the ACP connection
   // so it doesn't leak, and remove lingering tasks.
+  // However, if the agent is actively prompting (generating a response),
+  // keep it alive so it can finish in the background — the idle sweep
+  // will clean it up once it transitions back to "connected".
   useEffect(() => {
     return () => {
-      connDisconnectRef.current().catch(() => {})
+      if (statusRef.current !== "prompting") {
+        connDisconnectRef.current().catch(() => {})
+      }
       if (taskIdRef.current) {
         removeTask(taskIdRef.current)
       }