feat(player): disable metadata actions for ephemeral tracks

Library-bound actions (favorite, add-to-playlist, track info) require a
DB row to operate; ephemeral tracks live only in memory and would 404
on use. Surface them disabled rather than removed so the affordance
stays discoverable in the chrome — users still see the icon, the
tooltip explains why it's inert.

Surfaces wired
- NowPlayingBar: + and ♥ disabled when active track id >= 2^48.
- QueuePanel: now-playing ♥ + per-track Add to Playlist + Track Info
  in both queue and history menus disabled per-row by id range.
- ImmersiveControls + PlayerControlsCompact: ♥ disabled.
- ImmersivePlayer: passthrough prop to PlayerControlsCompact.
- MiniPlayerFooter / MiniPlayerWindowControls: no metadata actions in
  these surfaces, nothing to gate.

Detection is by id range (>= EPHEMERAL_ID_FLOOR), not by source string.
The setQueueForLocalTracks mapping rewrites `source: 'ephemeral'` to
`'local'` before the track reaches the queue, so a string-equality
check would never fire — id range matches the rest of the ephemeral
codebase (gapless carve-out, CUE boundary, seek offset, queue/now-
playing wipe).

Tooltip on the disabled state uses the new
`actions.unavailableForEphemeral` key, translated for en, es, de, fr, pt.

cc

src/lib/components/NowPlayingBar.svelte

@@ -95,6 +95,14 @@
     normalizationGain?: number | null;
     onToggleNormalization?: () => void;
     controlsDisabled?: boolean;
+    /**
+     * Hide the favorite + add-to-playlist buttons when the active track
+     * can't be persisted to library structures (today: ephemeral folder
+     * playback). Playback controls stay enabled — the user can still
+     * play / pause / skip / seek / volume; only the metadata-bound
+     * actions disappear.
+     */
+    metadataActionsDisabled?: boolean;
     explicit?: boolean;
     qconnectSessionSnapshot?: QconnectSessionSnapshot | null;
     onToggleQconnectConnection?: () => void | Promise<void>;
@@ -150,6 +158,7 @@
     normalizationGain = null,
     onToggleNormalization,
     controlsDisabled = false,
+    metadataActionsDisabled = false,
     explicit = false,
     qconnectSessionSnapshot = null,
     onToggleQconnectConnection,
@@ -491,23 +500,25 @@
 
       <button
         class="control-btn"
-        class:disabled={controlsDisabled}
+        class:disabled={controlsDisabled || metadataActionsDisabled}
-        disabled={controlsDisabled}
+        disabled={controlsDisabled || metadataActionsDisabled}
-        onclick={controlsDisabled ? undefined : onAddToPlaylist}
+        onclick={controlsDisabled || metadataActionsDisabled ? undefined : onAddToPlaylist}
-        title={$translateStore('actions.addToPlaylist')}
+        title={metadataActionsDisabled ? $translateStore('actions.unavailableForEphemeral') : $translateStore('actions.addToPlaylist')}
       >
         <Plus size={16} />
       </button>
 
       <button
         class="control-btn"
-        class:active={isFavorite && !controlsDisabled}
+        class:active={isFavorite && !controlsDisabled && !metadataActionsDisabled}
-        class:disabled={controlsDisabled}
+        class:disabled={controlsDisabled || metadataActionsDisabled}
-        disabled={controlsDisabled}
+        disabled={controlsDisabled || metadataActionsDisabled}
-        onclick={controlsDisabled ? undefined : onToggleFavorite}
+        onclick={controlsDisabled || metadataActionsDisabled ? undefined : onToggleFavorite}
-        title={isFavorite ? $translateStore('actions.removeFromFavorites') : $translateStore('actions.addToFavorites')}
+        title={metadataActionsDisabled
+          ? $translateStore('actions.unavailableForEphemeral')
+          : (isFavorite ? $translateStore('actions.removeFromFavorites') : $translateStore('actions.addToFavorites'))}
       >
-        <Heart size={16} fill={isFavorite ? 'currentColor' : 'none'} />
+        <Heart size={16} fill={isFavorite && !metadataActionsDisabled ? 'currentColor' : 'none'} />
       </button>
     </div>
 

src/lib/components/QueuePanel.svelte

@@ -29,6 +29,18 @@
     parental_warning?: boolean;
   }
 
+  // Mirrors EPHEMERAL_ID_FLOOR (1 << 48) in src-tauri/src/ephemeral_library.
+  // Track ids at or above this threshold come from the in-memory ephemeral
+  // cache, not the library DB. Favorites / playlists / track-info actions
+  // require a DB row and don't make sense for ephemeral tracks; the
+  // helper below gates the corresponding UI off so users don't get
+  // dead-end clicks.
+  const EPHEMERAL_ID_FLOOR = 1 << 48;
+  function isEphemeralQueueTrack(id: string | number | null | undefined): boolean {
+    if (id == null) return false;
+    return Number(id) >= EPHEMERAL_ID_FLOOR;
+  }
+
   interface IndexedQueueTrack {
     track: QueueTrack;
     originalIndex: number;
@@ -349,11 +361,15 @@
               </div>
               <button
                 class="np-favorite"
-                class:active={currentTrackFavorite}
+                class:active={currentTrackFavorite && !isEphemeralQueueTrack(currentTrack.id)}
-                onclick={toggleCurrentTrackFavorite}
+                class:disabled={isEphemeralQueueTrack(currentTrack.id)}
-                title={currentTrackFavorite ? $t('actions.removeFromFavorites') : $t('actions.addToFavorites')}
+                disabled={isEphemeralQueueTrack(currentTrack.id)}
+                onclick={isEphemeralQueueTrack(currentTrack.id) ? undefined : toggleCurrentTrackFavorite}
+                title={isEphemeralQueueTrack(currentTrack.id)
+                  ? $t('actions.unavailableForEphemeral')
+                  : (currentTrackFavorite ? $t('actions.removeFromFavorites') : $t('actions.addToFavorites'))}
               >
-                <Heart size={18} fill={currentTrackFavorite ? 'currentColor' : 'none'} />
+                <Heart size={18} fill={currentTrackFavorite && !isEphemeralQueueTrack(currentTrack.id) ? 'currentColor' : 'none'} />
               </button>
             </div>
           </div>
@@ -438,11 +454,23 @@
                           </button>
                         {/if}
 
-                        <button class="menu-item" onclick={(e) => handleAddToPlaylist(e, queueTrack.id)}>
+                        <button
+                          class="menu-item"
+                          class:disabled={isEphemeralQueueTrack(queueTrack.id)}
+                          disabled={isEphemeralQueueTrack(queueTrack.id)}
+                          onclick={(e) => { if (!isEphemeralQueueTrack(queueTrack.id)) handleAddToPlaylist(e, queueTrack.id); }}
+                          title={isEphemeralQueueTrack(queueTrack.id) ? $t('actions.unavailableForEphemeral') : ''}
+                        >
                           <ListPlus size={14} />
                           <span>{$t('actions.addToPlaylist')}</span>
                         </button>
-                        <button class="menu-item" onclick={(e) => handleShowTrackInfo(e, queueTrack.id)}>
+                        <button
+                          class="menu-item"
+                          class:disabled={isEphemeralQueueTrack(queueTrack.id)}
+                          disabled={isEphemeralQueueTrack(queueTrack.id)}
+                          onclick={(e) => { if (!isEphemeralQueueTrack(queueTrack.id)) handleShowTrackInfo(e, queueTrack.id); }}
+                          title={isEphemeralQueueTrack(queueTrack.id) ? $t('actions.unavailableForEphemeral') : ''}
+                        >
                           <Info size={14} />
                           <span>{$t('player.trackInfo')}</span>
                         </button>
@@ -497,11 +525,23 @@
                     </button>
                     {#if openHistoryMenuId === track.id}
                       <div class="track-context-menu">
-                        <button class="menu-item" onclick={(e) => handleAddToPlaylist(e, track.id)}>
+                        <button
+                          class="menu-item"
+                          class:disabled={isEphemeralQueueTrack(track.id)}
+                          disabled={isEphemeralQueueTrack(track.id)}
+                          onclick={(e) => { if (!isEphemeralQueueTrack(track.id)) handleAddToPlaylist(e, track.id); }}
+                          title={isEphemeralQueueTrack(track.id) ? $t('actions.unavailableForEphemeral') : ''}
+                        >
                           <ListPlus size={14} />
                           <span>{$t('actions.addToPlaylist')}</span>
                         </button>
-                        <button class="menu-item" onclick={(e) => handleShowTrackInfo(e, track.id)}>
+                        <button
+                          class="menu-item"
+                          class:disabled={isEphemeralQueueTrack(track.id)}
+                          disabled={isEphemeralQueueTrack(track.id)}
+                          onclick={(e) => { if (!isEphemeralQueueTrack(track.id)) handleShowTrackInfo(e, track.id); }}
+                          title={isEphemeralQueueTrack(track.id) ? $t('actions.unavailableForEphemeral') : ''}
+                        >
                           <Info size={14} />
                           <span>{$t('player.trackInfo')}</span>
                         </button>

src/lib/components/immersive/ImmersiveControls.svelte

@@ -30,6 +30,11 @@
     onToggleFavorite: () => void;
     onVolumeChange: (volume: number) => void;
     volumeLocked?: boolean;
+    /** Disable the favorite button when the active track lives outside
+     * the library (today: ephemeral folder playback). Heart stays visible
+     * but inert so the user understands the action exists; it just isn't
+     * meaningful for transient tracks. */
+    metadataActionsDisabled?: boolean;
   }
 
   let {
@@ -52,7 +57,8 @@
     onToggleRepeat,
     onToggleFavorite,
     onVolumeChange,
-    volumeLocked = false
+    volumeLocked = false,
+    metadataActionsDisabled = false
   }: Props = $props();
 </script>
 
@@ -121,13 +127,17 @@
   <div class="right-section">
     <button
       class="action-btn"
-      class:active={isFavorite}
+      class:active={isFavorite && !metadataActionsDisabled}
-      onclick={onToggleFavorite}
+      class:disabled={metadataActionsDisabled}
-      title={isFavorite ? $t('actions.removeFromFavorites') : $t('actions.addToFavorites')}
+      disabled={metadataActionsDisabled}
+      onclick={metadataActionsDisabled ? undefined : onToggleFavorite}
+      title={metadataActionsDisabled
+        ? $t('actions.unavailableForEphemeral')
+        : (isFavorite ? $t('actions.removeFromFavorites') : $t('actions.addToFavorites'))}
     >
       <Heart
         size={18}
-        fill={isFavorite ? 'currentColor' : 'none'}
+        fill={isFavorite && !metadataActionsDisabled ? 'currentColor' : 'none'}
       />
     </button>
 

src/lib/components/immersive/ImmersivePlayer.svelte

@@ -100,6 +100,10 @@
     onPlayHistoryTrack?: (trackId: string) => void;
     // Content flags
     explicit?: boolean;
+    /** Disable metadata-bound actions (favorite, etc) when the active
+     * track lives outside the library. Passed down to ImmersiveControls
+     * and PlayerControlsCompact. */
+    metadataActionsDisabled?: boolean;
   }
 
   let {
@@ -150,7 +154,8 @@
     onQueueClear,
     historyTracks = [],
     onPlayHistoryTrack,
-    explicit = false
+    explicit = false,
+    metadataActionsDisabled = false
   }: Props = $props();
 
   // UI State
@@ -778,6 +783,7 @@
       {onToggleShuffle}
       {onToggleRepeat}
       {onToggleFavorite}
+      {metadataActionsDisabled}
       {isInfinitePlay}
       {onToggleInfinitePlay}
       {onVolumeChange}

src/lib/components/immersive/PlayerControlsCompact.svelte

@@ -48,6 +48,10 @@
     onMinimize?: () => void;
     onToggleFullscreen?: () => void;
     onToggleMaximize?: () => void;
+    /** Disable favorite when active track lives outside the library
+     * (today: ephemeral folder playback). Heart stays visible but
+     * inert. */
+    metadataActionsDisabled?: boolean;
   }
 
   let {
@@ -76,7 +80,8 @@
     onClose,
     onMinimize,
     onToggleFullscreen,
-    onToggleMaximize
+    onToggleMaximize,
+    metadataActionsDisabled = false
   }: Props = $props();
 
   let progressRef: HTMLDivElement | null = $state(null);
@@ -220,11 +225,15 @@
       <div class="controls-group left">
         <button
           class="control-btn"
-          class:active={isFavorite}
+          class:active={isFavorite && !metadataActionsDisabled}
-          onclick={onToggleFavorite}
+          class:disabled={metadataActionsDisabled}
-          title={isFavorite ? $t('actions.removeFromFavorites') : $t('actions.addToFavorites')}
+          disabled={metadataActionsDisabled}
+          onclick={metadataActionsDisabled ? undefined : onToggleFavorite}
+          title={metadataActionsDisabled
+            ? $t('actions.unavailableForEphemeral')
+            : (isFavorite ? $t('actions.removeFromFavorites') : $t('actions.addToFavorites'))}
         >
-          <Heart size={12} fill={isFavorite ? 'currentColor' : 'none'} />
+          <Heart size={12} fill={isFavorite && !metadataActionsDisabled ? 'currentColor' : 'none'} />
         </button>
         <button
           class="control-btn"

src/lib/i18n/locales/de.json

@@ -39,6 +39,7 @@
     "addToPlaylist": "Zur Playlist hinzufügen",
     "addToFavorites": "Zur Bibliothek hinzufügen",
     "removeFromFavorites": "Aus Bibliothek entfernen",
+    "unavailableForEphemeral": "Nicht verfügbar für temporäre Ordner",
     "removeFromPlaylist": "Aus Playlist entfernen",
     "selectedTracks": "{count, plural, one {# Titel ausgewählt} other {# Titel ausgewählt}}",
     "select": "Auswählen",

src/lib/i18n/locales/en.json

@@ -40,6 +40,7 @@
     "addToPlaylist": "Add to Playlist",
     "addToFavorites": "Add to Library",
     "removeFromFavorites": "Remove from Library",
+    "unavailableForEphemeral": "Not available for ephemeral folders",
     "removeFromPlaylist": "Remove from Playlist",
     "selectedTracks": "{count, plural, one {# track selected} other {# tracks selected}}",
     "select": "Select",

src/lib/i18n/locales/es.json

@@ -39,6 +39,7 @@
     "addToPlaylist": "Agregar a Lista",
     "addToFavorites": "Agregar a Biblioteca",
     "removeFromFavorites": "Quitar de Biblioteca",
+    "unavailableForEphemeral": "No disponible para carpetas efímeras",
     "removeFromPlaylist": "Quitar del Playlist",
     "selectedTracks": "{count, plural, one {# canción seleccionada} other {# canciones seleccionadas}}",
     "select": "Seleccionar",

src/lib/i18n/locales/fr.json

@@ -39,6 +39,7 @@
     "addToPlaylist": "Ajouter à la playlist",
     "addToFavorites": "Ajouter à la bibliothèque",
     "removeFromFavorites": "Retirer de la bibliothèque",
+    "unavailableForEphemeral": "Non disponible pour les dossiers éphémères",
     "removeFromPlaylist": "Retirer de la playlist",
     "selectedTracks": "{count, plural, one {# titre sélectionné} other {# titres sélectionnés}}",
     "select": "Sélectionner",

src/lib/i18n/locales/pt.json

@@ -39,6 +39,7 @@
     "addToPlaylist": "Adicionar à Playlist",
     "addToFavorites": "Adicionar à biblioteca",
     "removeFromFavorites": "Remover da biblioteca",
+    "unavailableForEphemeral": "Indisponível para pastas efêmeras",
     "removeFromPlaylist": "Remover da Playlist",
     "selectedTracks": "{count, plural, one {# faixa selecionada} other {# faixas selecionadas}}",
     "select": "Selecionar",

src/routes/+page.svelte

@@ -6727,6 +6727,7 @@
         {isFavorite}
         onToggleFavorite={toggleFavorite}
         onAddToPlaylist={openAddToPlaylistModal}
+        metadataActionsDisabled={currentTrack != null && currentTrack.id >= (1 << 48)}
         onOpenQueue={toggleQueue}
         onOpenMiniPlayer={() => {
           void enterMiniplayerMode();
@@ -6832,6 +6833,7 @@
         onToggleRepeat={toggleRepeat}
         {isFavorite}
         onToggleFavorite={toggleFavorite}
+        metadataActionsDisabled={currentTrack != null && currentTrack.id >= (1 << 48)}
         lyricsLines={lyricsLines}
         lyricsActiveIndex={lyricsActiveIndex}
         lyricsActiveProgress={lyricsActiveProgress}