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/promoteStreamCache.ts

@@ -1,4 +1,4 @@
-import { buildStreamUrl } from '../api/subsonicStreamUrl';
+import { buildStreamUrlForServer } from '../api/subsonicStreamUrl';
 import type { Track } from './playerStoreTypes';
 import { invoke } from '@tauri-apps/api/core';
 import { useHotCacheStore } from './hotCacheStore';
@@ -25,7 +25,7 @@ export async function promoteCompletedStreamToHotCache(
       {
         trackId: track.id,
         serverId,
-        url: buildStreamUrl(track.id),
+        url: buildStreamUrlForServer(serverId, track.id),
         suffix: track.suffix || 'mp3',
         customDir,
       },