feat(api): Add GUI state manipulation hooks with thread-safe queueing

tests/test_hooks.py

@@ -68,6 +68,16 @@ def test_ipc_server_starts_and_responds():
         with urllib.request.urlopen(req) as response:
             assert response.status == 200
             assert app_mock.disc_entries == [{"role": "User", "content": "hi"}]
+
+        # Test GUI queue hook
+        req = urllib.request.Request("http://127.0.0.1:8999/api/gui", method="POST", data=json.dumps({"action": "set_value", "item": "test_item", "value": "test_value"}).encode("utf-8"), headers={'Content-Type': 'application/json'})
+        with urllib.request.urlopen(req) as response:
+            assert response.status == 200
+            # Instead of checking DPG (since we aren't running the real main loop in tests),
+            # check if it got queued in app_mock
+            assert hasattr(app_mock, '_pending_gui_tasks')
+            assert len(app_mock._pending_gui_tasks) == 1
+            assert app_mock._pending_gui_tasks[0] == {"action": "set_value", "item": "test_item", "value": "test_value"}
             
     finally:
         server.stop()