fix(web/player): auto-skip a failed track instead of dead-ending on "Try again"

A track that fails to load (e.g. a stale system-playlist snapshot pointing
at a rebuilt/removed file) hard-set the player to the 'error' state and
stranded the user on a "Try again" button that just re-queued the same
failing track. Now a load error advances to the next track; the error
state only surfaces once the whole queue has proven unplayable — every
track failed, or we reached the end. A failure streak capped at queue
length stops a fully-broken queue from cycling, and resets on the next
successful play.

Next (Track B cont.): self-heal a stale system-playlist / radio queue by
re-pulling the fresh snapshot on total failure, plus the Android
equivalent. Issue #968.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web/src/lib/player/store.svelte.ts

@@ -83,6 +83,12 @@ let _radioRefreshInFlight = false;
 // queue clears it).
 let _queueSource = $state<string | null>(null);
 
+// Track B (#968): consecutive load failures since the last successful
+// 'playing'. A bad track auto-advances instead of dead-ending; the streak
+// (capped against queue length) stops a fully-unplayable queue from
+// looping forever. Reset on a successful play and on a fresh playQueue.
+let _failureStreak = 0;
+
 let _audioEl: HTMLAudioElement | null = null;
 
 export const player = {
@@ -142,6 +148,7 @@ export function playQueue(
   _position = 0;
   _duration = 0;
   _error = null;
+  _failureStreak = 0;
 }
 
 export function togglePlay(): void {
@@ -263,6 +270,7 @@ export function reportStateFromAudio(
     case 'playing':
       _state = 'playing';
       _error = null;
+      _failureStreak = 0;
       return;
     case 'paused':
       _state = 'paused';
@@ -271,8 +279,7 @@ export function reportStateFromAudio(
       _state = 'loading';
       return;
     case 'error':
-      _state = 'error';
-      _error = detail ?? 'Playback failed.';
+      handleLoadFailure(detail);
       return;
     case 'ended':
       if (_repeat === 'one') {
@@ -301,6 +308,25 @@ export function reportStateFromAudio(
   }
 }
 
+// Track B (#968): a single failed track must not strand the player on the
+// "Try again" dead-end. Advance past it; only surface the error once the
+// whole queue has proven unplayable — every track failed, or we reached the
+// end with nothing playable. The streak cap (vs queue length) stops a
+// fully-broken queue from cycling forever instead of settling.
+function handleLoadFailure(detail?: string): void {
+  _failureStreak++;
+  if (_failureStreak < _queue.length && _index + 1 < _queue.length) {
+    _index++;
+    _position = 0;
+    _duration = 0;
+    _state = 'loading';
+    _error = null;
+    return;
+  }
+  _state = 'error';
+  _error = detail ?? 'Playback failed.';
+}
+
 export function enqueueTrack(t: TrackRef): void {
   _radioSeedId = null;  // M4c
   _queue = [..._queue, t];

web/src/lib/player/store.test.ts

@@ -288,6 +288,24 @@ describe('player store — shuffle + repeat + audio reports', () => {
     expect(player.state).toBe('error');
     expect(player.error).toBe('network lost');
   });
+
+  test('reportStateFromAudio("error") auto-advances past a bad track', () => {
+    playQueue([track('1'), track('2'), track('3')]);
+    reportStateFromAudio('error', 'boom');
+    expect(player.index).toBe(1);
+    expect(player.state).toBe('loading');
+    expect(player.error).toBeNull();
+  });
+
+  test('reportStateFromAudio("error") dead-ends once the whole queue is unplayable', () => {
+    playQueue([track('1'), track('2')]);
+    reportStateFromAudio('error', 'boom'); // track 1 fails → skip to track 2
+    expect(player.index).toBe(1);
+    expect(player.state).toBe('loading');
+    reportStateFromAudio('error', 'boom'); // track 2 also fails → exhausted
+    expect(player.state).toBe('error');
+    expect(player.error).toBe('boom');
+  });
 });
 
 import {