fix(ui): flush session persistence on close to prevent data loss

packages/ui/src/App.tsx

@@ -45,6 +45,7 @@ import {
   clearActiveParentSession,
   createSession,
   fetchSessions,
+  flushSessionPersistence,
   updateSessionAgent,
   updateSessionModel,
 } from "./stores/sessions"
@@ -245,6 +246,12 @@ const App: Component = () => {
       return
     }
 
+    try {
+      await flushSessionPersistence(instanceId)
+    } catch (error) {
+      log.error("Failed to flush session persistence before closing", error)
+    }
+
     clearActiveParentSession(instanceId)
 
     try {