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/store/applyQueueHistorySnapshot.ts

@@ -1,5 +1,6 @@
 import { reportNowPlaying } from '../api/subsonicScrobble';
 import { invoke } from '@tauri-apps/api/core';
+import { getPlaybackServerId } from '../utils/playback/playbackServer';
 import { getPlaybackSourceKind } from '../utils/playback/resolvePlaybackUrl';
 import { useAuthStore } from './authStore';
 import {
@@ -129,9 +130,9 @@ export function applyQueueHistorySnapshot(
           PlayerState,
           'normalizationNowDb' | 'normalizationTargetLufs' | 'normalizationEngineLive'
         >);
-  const authSnap = useAuthStore.getState();
+  const playbackSid = getPlaybackServerId();
   const playbackSourceUndo = nextTrack
-    ? getPlaybackSourceKind(nextTrack.id, authSnap.activeServerId ?? '', null)
+    ? getPlaybackSourceKind(nextTrack.id, playbackSid, null)
     : null;
   const playbackSourceFinal = keepPlaybackFromPrior && prior.currentPlaybackSource != null
     ? prior.currentPlaybackSource
@@ -186,7 +187,7 @@ export function applyQueueHistorySnapshot(
 
   if (!keepPlaybackFromPrior) {
     const { nowPlayingEnabled: npUndo } = useAuthStore.getState();
-    if (npUndo) reportNowPlaying(nextTrack.id);
+    if (npUndo) reportNowPlaying(nextTrack.id, getPlaybackServerId());
 
     queueUndoRestoreAudioEngine({
       generation: gen,