feat(qconnect): gate volume on renderer volume_remote_control capability

Add volume_remote_control to QconnectRendererInfo plus the
renderer_allows_remote_volume predicate (absent => allowed, only an explicit
non-1 value disables). Parse it from device_info.capabilities in the ADD and
UPDATE renderer paths, and short-circuit set_volume_if_remote when the active
renderer disallows remote volume (returns handled no-op so the frontend does
not fall back to local). Frontend surfaces volume_remote_control in the session
snapshot, derives a unified volume lock + reason, guards handleVolumeChange,
and shows a distinct player.volumeLockedRemote tooltip (added to all 5 locales).

cc

src/lib/components/NowPlayingBar.svelte

@@ -106,6 +106,9 @@
     qconnectBusy?: boolean;
     showQconnectDevButton?: boolean;
     volumeLocked?: boolean;
+    // P1-5: distinguishes the hardware (ALSA Direct) lock from the remote
+    // renderer (cast device) lock so the tooltip can be specific.
+    volumeLockedReason?: 'hardware' | 'remote';
     bufferProgress?: number | null;
   }
 
@@ -162,6 +165,7 @@
     qconnectBusy = false,
     showQconnectDevButton = false,
     volumeLocked = false,
+    volumeLockedReason = 'hardware',
     bufferProgress = null,
   }: Props = $props();
 
@@ -823,7 +827,9 @@
         {#if volumeLocked}
           <button
             class="control-btn volume-btn"
-            title={$translateStore('player.volumeLockedHw')}
+            title={volumeLockedReason === 'remote'
+              ? $translateStore('player.volumeLockedRemote')
+              : $translateStore('player.volumeLockedHw')}
             disabled
           >
             <Volume2 size={16} />

src/lib/i18n/locales/de.json

@@ -1540,6 +1540,7 @@
     "volumeUp": "Lauter",
     "volumeDown": "Leiser",
     "volumeLockedHw": "Lautstärke auf 100% fixiert — ALSA Direct hw: (am DAC/Hardware einstellen)",
+    "volumeLockedRemote": "Lautstärkeregelung durch das Cast-Gerät deaktiviert",
     "clearQueue": "Warteschlange leeren",
     "queueEmpty": "Warteschlange ist leer",
     "queueEmptyDescription": "Suche nach Musik oder durchsuchen Sie Ihre Bibliothek, um Titel hinzuzufügen.",

src/lib/i18n/locales/en.json

@@ -1542,6 +1542,7 @@
     "volumeUp": "Increase volume",
     "volumeDown": "Decrease volume",
     "volumeLockedHw": "Volume locked at 100% — ALSA Direct hw: (adjust at DAC/hardware level)",
+    "volumeLockedRemote": "Volume control disabled by the cast device",
     "clearQueue": "Clear Queue",
     "queueEmpty": "Queue is empty",
     "queueEmptyDescription": "Search for music or browse your library to add tracks.",

src/lib/i18n/locales/es.json

@@ -1540,6 +1540,7 @@
     "volumeUp": "Subir volumen",
     "volumeDown": "Bajar volumen",
     "volumeLockedHw": "Volumen fijo al 100% — ALSA Direct hw: (ajusta desde el DAC/hardware)",
+    "volumeLockedRemote": "El control de volumen está deshabilitado por el dispositivo",
     "clearQueue": "Limpiar Cola",
     "queueEmpty": "La cola está vacía",
     "queueEmptyDescription": "Busca música o explora tu biblioteca para agregar pistas.",

src/lib/i18n/locales/fr.json

@@ -1540,6 +1540,7 @@
     "volumeUp": "Augmenter le volume",
     "volumeDown": "Diminuer le volume",
     "volumeLockedHw": "Volume verrouillé à 100% — ALSA Direct hw: (réglez au niveau DAC/matériel)",
+    "volumeLockedRemote": "Contrôle du volume désactivé par l'appareil de diffusion",
     "clearQueue": "Vider la file d'attente",
     "queueEmpty": "La file d'attente est vide",
     "queueEmptyDescription": "Recherchez de la musique ou parcourez votre bibliothèque pour ajouter des titres.",

src/lib/i18n/locales/pt.json

@@ -1540,6 +1540,7 @@
     "volumeUp": "Aumentar volume",
     "volumeDown": "Diminuir volume",
     "volumeLockedHw": "Volume fixo em 100% — ALSA Direct hw: (ajuste no DAC/hardware)",
+    "volumeLockedRemote": "Controle de volume desativado pelo dispositivo de transmissão",
     "clearQueue": "Limpar Fila",
     "queueEmpty": "A fila está vazia",
     "queueEmptyDescription": "Pesquise músicas ou navegue pela sua biblioteca para adicionar faixas.",

src/lib/services/qconnectRuntime.ts

@@ -32,6 +32,9 @@ export type QconnectRendererInfo = {
   brand?: string | null;
   model?: string | null;
   device_type?: number | null;
+  // P1-5: capabilities.volume_remote_control. 1 == ALLOWED. null/undefined ==
+  // not advertised (treated as allowed). Any other value disables remote volume.
+  volume_remote_control?: number | null;
 };
 
 export type QconnectSessionSnapshot = {

src/routes/+page.svelte

@@ -1125,6 +1125,26 @@
   const qconnectPeerRendererActive = $derived(
     isQconnectPeerRendererActive(qobuzConnectSessionSnapshot)
   );
+  // P1-5: respect the active renderer's volume_remote_control capability.
+  // Absent (null/undefined) => allowed; only an explicit non-1 value disables.
+  const qconnectRemoteVolumeAllowed = $derived.by(() => {
+    if (!qconnectPeerRendererActive) return true;
+    const snap = qobuzConnectSessionSnapshot;
+    const activeId = snap?.active_renderer_id ?? null;
+    const info = snap?.renderers?.find((r) => r.renderer_id === activeId) ?? null;
+    const vrc = info?.volume_remote_control;
+    return vrc == null || vrc === 1;
+  });
+  // P1-5: unified volume-lock state shared by the now-playing bar + immersive
+  // player. Hardware lock applies only locally; remote lock applies when a peer
+  // renderer is active and disallows remote volume.
+  const qconnectVolumeLocked = $derived(
+    (isAlsaDirectHw && !qconnectPeerRendererActive) ||
+      (qconnectPeerRendererActive && !qconnectRemoteVolumeAllowed)
+  );
+  const qconnectVolumeLockedReason: 'hardware' | 'remote' = $derived(
+    qconnectPeerRendererActive && !qconnectRemoteVolumeAllowed ? 'remote' : 'hardware'
+  );
   const qconnectSuppressLocalPlaybackAutomation = $derived(
     shouldQconnectSuppressLocalPlaybackAutomation(
       isQobuzConnectConnected,
@@ -2887,6 +2907,8 @@
   async function handleVolumeChange(newVolume: number) {
     // ALSA Direct hw: locks volume at 100% — unless controlling a remote renderer
     if (isAlsaDirectHw && !qconnectPeerRendererActive) return;
+    // P1-5: the active remote renderer disallows remote volume control.
+    if (qconnectPeerRendererActive && !qconnectRemoteVolumeAllowed) return;
 
     try {
       const handledRemotely = await invoke<boolean>('v2_qconnect_set_volume_if_remote', { volume: newVolume });
@@ -7141,7 +7163,8 @@
         onToggleQconnectConnection={handleQobuzConnectButton}
         qconnectBusy={qobuzConnectBusy}
         {showQconnectDevButton}
-        volumeLocked={isAlsaDirectHw && !qconnectPeerRendererActive}
+        volumeLocked={qconnectVolumeLocked}
+        volumeLockedReason={qconnectVolumeLockedReason}
         {bufferProgress}
       />
     {:else}
@@ -7164,7 +7187,8 @@
         onToggleQconnectConnection={handleQobuzConnectButton}
         qconnectBusy={qobuzConnectBusy}
         {showQconnectDevButton}
-        volumeLocked={isAlsaDirectHw && !qconnectPeerRendererActive}
+        volumeLocked={qconnectVolumeLocked}
+        volumeLockedReason={qconnectVolumeLockedReason}
       />
     {/if}
 
@@ -7198,7 +7222,7 @@
         {volume}
         onVolumeChange={handleVolumeChange}
         onToggleMute={handleToggleMute}
-        volumeLocked={isAlsaDirectHw && !qconnectPeerRendererActive}
+        volumeLocked={qconnectVolumeLocked}
         {isShuffle}
         onToggleShuffle={toggleShuffle}
         {repeatMode}