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/ui/windows/console_command_executor.cpp

@@ -121,6 +121,12 @@ void FullNodeConsoleExecutor::submit(const std::string& cmd)
     if (worker) {
         in_flight_.fetch_add(1);   // gates busy() so the input is disabled until this returns
         worker->post([rpc, method, params, this]() -> rpc::RPCWorker::MainCb {
+            // Drops the busy gate when the worker job ends, however it ends. The gate used to drop in the
+            // MainCb, which is lost when teardown stops the fast worker undrained, leaving busy() stuck.
+            struct ReleaseGate {
+                std::atomic<int>& n;
+                ~ReleaseGate() { n.fetch_sub(1); }
+            } gate{in_flight_};
             std::string result_str;
             bool is_error = false;
             try {
@@ -129,14 +135,19 @@ void FullNodeConsoleExecutor::submit(const std::string& cmd)
             } catch (const std::exception& e) {
                 result_str = e.what();
                 is_error = true;
+            } catch (...) {
+                result_str = "RPC failed (unknown error)";
+                is_error = true;
             }
-            return [this, result_str, is_error]() {
-                in_flight_.fetch_sub(1);
+            {
+                // Publish the result before the gate drops, so a non-busy console always has it queued.
+                std::lock_guard<std::mutex> lk(results_mutex_);
+                results_.push_back({result_str, is_error});
+            }
+            return [this]() {
                 // A Console command may have changed the wallet (a send, an import, a new address): the
                 // scans gated on change signals must look again. (Main thread: this is a drained callback.)
                 if (app_) app_->noteWalletMutation();
-                std::lock_guard<std::mutex> lk(results_mutex_);
-                results_.push_back({result_str, is_error});
             };
         });
     } else {