Show which tracks failed to match in sync completion toast

When a playlist sync has unmatched tracks sent to wishlist, the
completion toast now shows the specific track names instead of just
a count. Uses warning style so it stands out. The unmatched track
list is included in the sync state result so it's available for
both live status polling and notification history.

Addresses #272 — silent sync failures where users couldn't tell
which tracks out of 150+ failed to match their Plex library.

web_server.py

@@ -36657,12 +36657,21 @@ def _run_sync_task(playlist_id, playlist_name, tracks_json, automation_id=None,
 
         # Update final state on completion
         # Convert result to JSON-serializable dict (datetime/errors can't be emitted via SocketIO)
-        # Exclude match_details — large, not needed for live status, saved to DB separately
+        # Exclude match_details (large) but include a summary of unmatched tracks
         result_dict = {
             k: (v.isoformat() if hasattr(v, 'isoformat') else v)
             for k, v in result.__dict__.items()
             if k != 'match_details'
         }
+        # Include unmatched track names so the frontend can show which tracks failed
+        match_details = getattr(result, 'match_details', None)
+        if match_details:
+            unmatched_summary = [
+                {'name': d.get('name', ''), 'artist': d.get('artist', ''), 'image_url': d.get('image_url', '')}
+                for d in match_details if d.get('status') == 'not_found'
+            ]
+            if unmatched_summary:
+                result_dict['unmatched_tracks'] = unmatched_summary
         with sync_lock:
             sync_states[playlist_id] = {
                 "status": "finished",

webui/static/script.js

@@ -16296,9 +16296,13 @@ function updateCardToDefault(playlistId, finalState = null) {
 
             // Check if any tracks were added to wishlist
             const wishlistCount = finalState.progress?.wishlist_added_count || finalState.result?.wishlist_added_count || 0;
+            const unmatchedTracks = finalState.progress?.unmatched_tracks || finalState.result?.unmatched_tracks || [];
             const playlistName = card.querySelector('.playlist-card-name').textContent;
 
-            if (wishlistCount > 0) {
+            if (wishlistCount > 0 && unmatchedTracks.length > 0) {
+                const trackList = unmatchedTracks.map(t => `${t.artist} - ${t.name}`).join(', ');
+                showToast(`Sync complete for "${playlistName}". ${wishlistCount} not found in library: ${trackList}`, 'warning');
+            } else if (wishlistCount > 0) {
                 showToast(`Sync complete for "${playlistName}". Added ${wishlistCount} missing track${wishlistCount > 1 ? 's' : ''} to wishlist.`, 'success');
             } else {
                 showToast(`Sync complete for "${playlistName}"`, 'success');