fix: multi-tab concurrency and metadata sync improvements

backend/app/services/browser_session_service.py

@@ -141,6 +141,8 @@ class BrowserSessionService:
             self._sessions[session.id] = session
             self._profiles[profile_key] = session.id
             self._touch(session.id)
+            # Register listeners for the initial tab
+            self._setup_tab_listeners(session, page)
             # Register page capture for multi-tab support
             context.on("page", lambda p: self._handle_new_page(session, p))
             # Evict again after adding the new session so cap is enforced immediately
@@ -160,14 +162,31 @@ class BrowserSessionService:
 
     def _handle_new_page(self, session: BrowserSession, page: Any) -> None:
         """Capture a new page opened by the remote browser (e.g. target="_blank")."""
+        asyncio.create_task(self._register_new_page(session, page))
+
+    def _setup_tab_listeners(self, session: BrowserSession, page: Any) -> None:
+        """Register navigation and state listeners to bump tab_revision."""
+        def bump_revision(_=None):
+            session.tab_revision += 1
+
+        page.on("domcontentloaded", bump_revision)
+        page.on("load", bump_revision)
+        page.on("framenavigated", bump_revision)
+        page.on("close", bump_revision)
+
+    async def _register_new_page(self, session: BrowserSession, page: Any) -> None:
         tab_id = uuid4().hex
         tab = BrowserTab(id=tab_id, page=page, created_at=asyncio.get_event_loop().time())
-        session.tabs[tab_id] = tab
-        session.active_tab_id = tab_id
-        session.tab_revision += 1
-        logger.info("session %s: captured new tab %s (total: %d)", session.id[:12], tab_id[:8], len(session.tabs))
+        
+        async with session.lock:
+            session.tabs[tab_id] = tab
+            session.active_tab_id = tab_id
+            session.tab_revision += 1
+            logger.info("session %s: captured new tab %s (total: %d)", session.id[:12], tab_id[:8], len(session.tabs))
+
+        self._setup_tab_listeners(session, page)
         # Best-effort: bring to front and reset zoom
-        asyncio.create_task(self._init_new_tab(session, tab))
+        await self._init_new_tab(session, tab)
 
     async def _init_new_tab(self, session: BrowserSession, tab: BrowserTab) -> None:
         try:
@@ -399,7 +418,8 @@ class BrowserSessionService:
         tabs = []
         # We might need to prune closed pages during state generation too
         closed_ids = []
-        for tid, tab in session.tabs.items():
+        # Use list() to avoid RuntimeError if tabs dict changes during iteration
+        for tid, tab in list(session.tabs.items()):
             if tab.page.is_closed():
                 closed_ids.append(tid)
                 continue
@@ -734,6 +754,8 @@ class BrowserSessionService:
             )
             self._sessions[session.id] = session
             self._touch(session.id)
+            # Register listeners for the initial tab
+            self._setup_tab_listeners(session, page)
             # Register page capture
             context.on("page", lambda p: self._handle_new_page(session, p))
         # Start CDP network capture BEFORE the initial page load,