fix(playback): pin queue playback to source server when browsing another library (#717)

* fix(playback): pin queue streams, cover art, and library links to queue server

When the active server changes while a queue from another server is playing,
keep streams and UI on queueServerId; switch back for artist/album links and
queue or player-bar context menus.

* fix(playback): switch to queue server when opening Now Playing

Ensure active server matches queueServerId before Subsonic fetches on the
Now Playing page, mobile player route, and queue info panel; scope caches
by server id.

* docs(credits): mention Now Playing in PR #717 contribution line

* fix(playback): route scrobble and queue sync to queue server

Address PR review: apiForServer for scrobble/now-playing/savePlayQueue,
clear queueServerId on server removal, mini-player queueServerId sync,
block cross-server enqueue with toast, and regression tests.

src/components/MiniPlayer.tsx

@@ -1,8 +1,9 @@
-import { buildCoverArtUrl, coverArtCacheKey } from '../api/subsonicStreamUrl';
+import { usePlaybackCoverArt } from '../hooks/usePlaybackCoverArt';
 import { useEffect, useMemo, useRef, useState } from 'react';
 import { emit } from '@tauri-apps/api/event';
 import { invoke } from '@tauri-apps/api/core';
 import { useTranslation } from 'react-i18next';
+import { usePlayerStore } from '../store/playerStore';
 import { registerQueueDragHitTest } from '../contexts/DragDropContext';
 import MiniContextMenu from './MiniContextMenu';
 import type { MiniSyncPayload, MiniControlAction, MiniTrackInfo } from '../utils/miniPlayerBridge';
@@ -63,6 +64,7 @@ export default function MiniPlayer() {
   useMiniSync({
     onSync: (payload) => {
       setState(payload);
+      usePlayerStore.setState({ queueServerId: payload.queueServerId ?? null });
       if (payload.track?.duration) setDuration(payload.track.duration);
       if (typeof payload.volume === 'number') setVolumeState(payload.volume);
     },
@@ -138,14 +140,7 @@ export default function MiniPlayer() {
   }, [queueOpen, state.queueIndex]);
 
   const { track, isPlaying } = state;
-  const miniCoverSrc = useMemo(
-    () => (track?.coverArt ? buildCoverArtUrl(track.coverArt, 300) : ''),
-    [track?.coverArt],
-  );
-  const miniCoverKey = useMemo(
-    () => (track?.coverArt ? coverArtCacheKey(track.coverArt, 300) : ''),
-    [track?.coverArt],
-  );
+  const { src: miniCoverSrc, cacheKey: miniCoverKey } = usePlaybackCoverArt(track?.coverArt, 300);
   const progress = duration > 0 ? Math.min(100, (currentTime / duration) * 100) : 0;
 
   return (