feat(voice): add on-device Miao Zhang Gui wake word

Add an optional local wake response prompt configuration. The prompt asset is intentionally not included yet.

components/control_plane/src/multimodal/control_plane_multimodal_runtime.c

@@ -575,6 +575,16 @@ static void control_plane_multimodal_event_bridge(control_plane_multimodal_event
                 ESP_LOGI(TAG, "Pause uplink during TTS responding");
                 control_plane_multimodal_stop_uplink();
             }
+#if CONFIG_TQ_PTT_MODE_CLICK_TO_TALK
+            if (!control_plane_voice_turn_is_idle()) {
+                /*
+                 * The server response closes this one-shot voice turn.  Once
+                 * teardown reaches IDLE, the local listener can resume with
+                 * AEC-clean PCM and accept 喵掌柜 while TTS is playing.
+                 */
+                control_plane_set_ptt_active(false);
+            }
+#endif
             break;
         }