batch3 T3: broker user channel + /api/ws/user + project/session/inference emits

- broker.subscribeUser/publishUser via separate user topics map
- /api/ws/user WS route subscribes to the user channel
- projects/sessions POST/DELETE handlers emit lifecycle frames
- inference 3 terminal-state sites emit session_updated with RETURNING

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/server/src/routes/ws.ts

@@ -43,4 +43,23 @@ export function registerWebSocket(
       socket.on('error', () => unsubscribe());
     }
   );
+
+  app.get('/api/ws/user', { websocket: true }, async (socket, req) => {
+    const user = req.user;
+    if (!user) {
+      socket.close(1008, 'unauthenticated');
+      return;
+    }
+    // No snapshot — user channel is purely live updates.
+    const unsubscribe = broker.subscribeUser(user, (frame) => {
+      if (socket.readyState !== socket.OPEN) return;
+      try {
+        socket.send(JSON.stringify(frame));
+      } catch (err) {
+        app.log.warn({ err, user }, 'user ws send failed');
+      }
+    });
+    socket.on('close', () => unsubscribe());
+    socket.on('error', () => unsubscribe());
+  });
 }