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/hooks/usePlaybackLibraryNavigate.ts

@@ -0,0 +1,12 @@
+import { useCallback } from 'react';
+import { useNavigate } from 'react-router-dom';
+import { ensurePlaybackServerActive } from '../utils/playback/playbackServer';
+
+/** Navigate to library routes for the playing queue — switches to {@link queueServerId} when needed. */
+export function usePlaybackLibraryNavigate() {
+  const navigate = useNavigate();
+  return useCallback(async (path: string) => {
+    await ensurePlaybackServerActive();
+    navigate(path);
+  }, [navigate]);
+}