fix(console): release busy gate when the fast worker stops

When the daemon disconnects, teardown stops the fast RPC worker without
draining its queued main-thread callbacks. The console busy gate was
released inside that callback, so a command whose callback was discarded
left the input disabled for the rest of the session.

- The busy gate now drops from an RAII guard at the end of the worker
  job itself, so it is released however the job ends: success, error, or
  a worker torn down undrained.
- The result is published to the console before the gate drops, so a
  freed-up console always has the output queued.
- An unknown, non-std::exception failure is now caught and reported
  instead of escaping the job.

User-visible: the Console input can no longer stay stuck disabled after
a reconnect.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app_network.cpp

@@ -943,7 +943,7 @@ void App::onDisconnected(const std::string& reason)
     // curl_easy_perform unblocks and stop()'s join() returns promptly (no UI freeze).
     if (fast_rpc_) fast_rpc_->requestAbort();
     if (fast_worker_) {
-        fast_worker_->stop();
+        fast_worker_->stop();   // undrained MainCbs are lost; console busy gate is released worker-side
         // Drop the stopped worker so onConnected recreates and starts a fresh one. Keeping a
         // stopped-but-present worker would defeat onConnected's `if (!fast_worker_)` guard, leaving
         // the fast lane dead for the rest of the session — which silently stalls the opid poll