web: add error surfacing

web/frontend/src/api/player.tsx

@@ -28,6 +28,7 @@ export interface PlaylistItem {
   id: number;
   playing: boolean | null;
   metadata?: Metadata;
+  playbackError?: string;
 }
 
 export const getDisplayTitle = (item: PlaylistItem): string => {
@@ -62,6 +63,7 @@ export enum ServerEvent {
   FavoritesUpdate     = "favorites_update",
   MetadataUpdate      = "metadata_update",
   MPDUpdate           = "mpd_update",
+  PlaybackError       = "playback_error",
   ScreenShare         = "screen_share",
 }
 

web/frontend/src/components/App.tsx

@@ -199,6 +199,7 @@ const App: React.FC = () => {
       case ServerEvent.NowPlayingUpdate:
       case ServerEvent.MetadataUpdate:
       case ServerEvent.MPDUpdate:
+      case ServerEvent.PlaybackError:
         fetchPlaylist();
         fetchNowPlaying();
         break;

web/frontend/src/components/SongRow.tsx

@@ -1,6 +1,6 @@
 import classNames from 'classnames';
 import React, { useState, useRef, useEffect, ReactNode } from 'react';
-import { FaPlay, FaVolumeUp, FaVolumeOff } from 'react-icons/fa';
+import { FaPlay, FaVolumeUp, FaVolumeOff, FaExclamationTriangle } from 'react-icons/fa';
 import { getDisplayTitle, PlaylistItem } from '../api/player';
 
 export enum PlayState {
@@ -19,6 +19,7 @@ export interface SongRowProps {
 
 const SongRow: React.FC<SongRowProps> = ({ song, auxControl, playState, onDelete, onPlay }) => {
   const [showDeleteConfirm, setShowDeleteConfirm] = useState(false);
+  const [showErrorDetails, setShowErrorDetails] = useState(false);
   const buttonRef = useRef<HTMLButtonElement>(null);
   
   useEffect(() => {
@@ -38,6 +39,7 @@ const SongRow: React.FC<SongRowProps> = ({ song, auxControl, playState, onDelete
   }, [showDeleteConfirm]);
   
   const displayTitle = getDisplayTitle(song);
+  const hasError = !!song.playbackError;
   
   return (
     <div className={classNames(
@@ -46,16 +48,46 @@ const SongRow: React.FC<SongRowProps> = ({ song, auxControl, playState, onDelete
       "bg-black/30": playState === PlayState.NotPlaying,
     })}>
       <div className="flex flex-row gap-2">
-        <button 
-          className="text-white/40 hover:text-white transition-colors px-3 py-1 rounded"
-          onClick={onPlay}
-        >
-          {
-            playState === PlayState.Playing ? <FaVolumeUp size={12} /> 
-            : playState === PlayState.Paused ? <FaVolumeOff size={12} /> 
-            : <FaPlay size={12} />
-          }
-        </button>
+        <div className="relative">
+          <button 
+            className={classNames(
+              "transition-colors px-3 py-1 rounded", 
+              hasError ? "text-amber-300 hover:text-amber-100" : "text-white/40 hover:text-white"
+            )}
+            onClick={() => {
+              if (hasError) {
+                setShowErrorDetails((prev) => !prev);
+              } else {
+                onPlay();
+              }
+            }}
+            onMouseEnter={() => {
+              if (hasError) {
+                setShowErrorDetails(true);
+              }
+            }}
+            onMouseLeave={() => {
+              if (hasError) {
+                setShowErrorDetails(false);
+              }
+            }}
+            title={hasError ? song.playbackError : undefined}
+          >
+            {
+              hasError ? <FaExclamationTriangle size={12} /> : 
+              playState === PlayState.Playing ? <FaVolumeUp size={12} /> 
+              : playState === PlayState.Paused ? <FaVolumeOff size={12} /> 
+              : <FaPlay size={12} />
+            }
+          </button>
+
+          {hasError && showErrorDetails && (
+            <div className="absolute z-10 top-full left-0 mt-1 w-64 p-2 text-xs text-white bg-red-600/90 rounded shadow-lg">
+              <div className="font-semibold mb-1">Playback error</div>
+              <div className="break-words">{song.playbackError}</div>
+            </div>
+          )}
+        </div>
       </div>
       
       <div className="flex-grow min-w-0">