feat(qconnect): auto-skip remote track on PlaybackError

Consumer maps PlaybackError -> handleSkipForward for streamable/network/
not-found failures on the current queue item; toast otherwise. Predicate
shouldAutoSkipOnPlaybackError unit-tested. i18n keys added in 5 locales.

cc

src/routes/+page.svelte

@@ -362,7 +362,9 @@
   import {
     replacePlaybackQueue,
     assessQconnectQueueSync,
-    syncQconnectQueueFromTracks
+    syncQconnectQueueFromTracks,
+    shouldAutoSkipOnPlaybackError,
+    type QconnectPlaybackErrorPayload
   } from '$lib/services/queuePlaybackService';
   import type {
     QconnectDiagnosticsPayload,
@@ -5774,6 +5776,21 @@
             }
           }
 
+          // Renderer reported a per-track playback failure. Auto-skip the
+          // failed track if it is the one currently playing and the error is a
+          // deterministic per-track failure; otherwise surface a toast.
+          if ('PlaybackError' in payloadObj) {
+            const pe = payloadObj.PlaybackError as QconnectPlaybackErrorPayload;
+            const currentQid =
+              qobuzConnectRendererSnapshot?.current_track?.queue_item_id ?? null;
+            if (shouldAutoSkipOnPlaybackError(pe, currentQid)) {
+              showToast($t('qconnect.trackUnavailableSkipping'), 'warning');
+              void handleSkipForward();
+            } else {
+              showToast($t('qconnect.trackPlaybackError'), 'error');
+            }
+          }
+
           // Sync QBZ local queue when QConnect remote queue changes or
           // renderer commands move the current track (next/prev from controllers).
           const needsQueueSync =