apps: canvas-chat App Builder seeds + sync meta.json + stale-approval filter

App Builder launched from canvas chat now seeds the React template and
registers an Output row tied to the session id, so the Apps sidebar
lights up immediately. Adds a post-session-complete sync that reads
meta.json from the workspace folder and updates the Output row's name
and description, ending the 'Untitled App' problem. Also adds a stale-
approval filter to the WS replay: resolved approvals no longer
resurrect as dead cards when the user navigates back to a chat.

frontend/src/shared/ws/WebSocketManager.ts

@@ -24,6 +24,7 @@ import {
 } from '../state/agentsSlice';
 import { streamStart, streamDelta, streamEnd } from '../state/streamingSlice';
 import { addBrowserCardFromBackend, removeBrowserCard, setBrowserCardPosition, setGlowingBrowserCards, GRID_GAP } from '../state/dashboardLayoutSlice';
+import { upsertOutput } from '../state/outputsSlice';
 import { getAuthToken } from '../config';
 import { notifyAgentCompletion } from '../notifications';
 
@@ -488,6 +489,16 @@ class WebSocketManager {
         }
         break;
 
+      case 'agent:output_upserted':
+        // Emitted by the backend when an Output row is created (canvas-launched
+        // App Builder seed) or updated (post-session meta.json sync). The
+        // upsert reducer merges over an existing row so a UI that already
+        // loaded the row doesn't lose locally-applied fields.
+        if (data.output && data.output.id) {
+          store.dispatch(upsertOutput(data.output));
+        }
+        break;
+
       case 'agent:stream_start':
       case 'agent:stream_delta':
       case 'agent:stream_end':