fix(multimodal): recover stalled downstream sessions

components/platform/include/platform.h

@@ -46,6 +46,7 @@ typedef struct {
     void (*on_started)(void *user_data);
     void (*on_completed)(void *user_data);
     void (*on_stopped)(void *user_data);
+    void (*on_stalled)(void *user_data);
     void *user_data;
 } platform_multimodal_downstream_playback_callbacks_t;
 

components/platform/internal/multimodal/audio_pipeline.h

@@ -20,6 +20,7 @@ typedef enum {
     MULTIMODAL_AUDIO_DOWNSTREAM_PLAYBACK_STARTED = 0,
     MULTIMODAL_AUDIO_DOWNSTREAM_PLAYBACK_COMPLETED,
     MULTIMODAL_AUDIO_DOWNSTREAM_PLAYBACK_STOPPED,
+    MULTIMODAL_AUDIO_DOWNSTREAM_PLAYBACK_STALLED,
 } multimodal_audio_downstream_playback_event_type_t;
 
 typedef struct {

components/platform/src/multimodal/audio_pipeline/audio_pipeline_runtime_impl.c

@@ -1774,6 +1774,11 @@ static void notify_downstream_playback_stopped(void)
     notify_downstream_playback_finished(MULTIMODAL_AUDIO_DOWNSTREAM_PLAYBACK_STOPPED);
 }
 
+static void notify_downstream_playback_stalled(void)
+{
+    notify_downstream_playback_finished(MULTIMODAL_AUDIO_DOWNSTREAM_PLAYBACK_STALLED);
+}
+
 static void abort_downstream_response_after_active_stall(multimodal_audio_ctx_t *ctx,
                                                          uint32_t idle_ms)
 {
@@ -1781,7 +1786,7 @@ static void abort_downstream_response_after_active_stall(multimodal_audio_ctx_t
              "Downstream protection watchdog: abort stalled response idle_ms=%u",
              (unsigned)idle_ms);
     (void)advance_downstream_playback_generation();
-    notify_downstream_playback_stopped();
+    notify_downstream_playback_stalled();
     update_downstream_response_state(false, false);
     if (audio_get_downstream_playback_task(ctx) != NULL ||
         audio_get_downstream_playback_starting(ctx)) {

components/platform/src/runtime/platform_multimodal_runtime.c

@@ -243,6 +243,11 @@ static void platform_multimodal_downstream_playback_bridge(
                 callbacks.on_stopped(callbacks.user_data);
             }
             break;
+        case MULTIMODAL_AUDIO_DOWNSTREAM_PLAYBACK_STALLED:
+            if (callbacks.on_stalled != NULL) {
+                callbacks.on_stalled(callbacks.user_data);
+            }
+            break;
         default:
             break;
     }