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/config/settingsCredits.ts

@@ -112,6 +112,7 @@ const CONTRIBUTOR_ENTRIES = [
       'Internet Radio: portal add/edit station modal to document.body — fixes clipped modal on empty library (report: voidboywannabe on Psysonic Discord) (PR #699)',
       'Now Playing: composite list keys on similar artists, album-card tracklist, and top songs — avoids duplicate React keys when Subsonic repeats ids (PR #703)',
       'Search: share links in live/mobile search + queue preview modal (PR #716)',
+      'Multi-server: pin queue streams, cover art, links, context menu, and Now Playing to queue server (PR #717)',
     ],
   },
   {