Rename the Arrs tab to Media Stack, now that it is one

It covers the pipeline rather than only acquisition: the arrs, the jobs that run
over the same files, and the servers that play them. The label moves; the tab id,
file and URL do not, so bookmarks and the cache key keep working.

The settings card widens with it — Play State Sync, Media Permissions, Media
Cleaner, Emby and Jellyfin were reachable only through the Settings catch-all,
which is a long way to go for a setting named after the page you are on. Match
is whole-word, so "Intermediate Sync" is not caught by "media"; section count is
unchanged at 126 with the same 5 gaps, so nothing was taken from another tab.

Plugin/unraid/pages/arrs.php

@@ -1,7 +1,7 @@
 <?php
 // ═══════════════════════════════════════════════════════════════════════════════════════════════
 // PURPOSE
-//   Arrs tab. Library counts, queue state, root folders and recent cleanup/discovery activity
+//   Media Stack tab. Library counts, queue state, root folders and recent cleanup/discovery activity
 //   for every Sonarr / Radarr / Lidarr instance across all nodes.
 //
 // DESIGN PRINCIPLES
@@ -115,7 +115,7 @@ require_once dirname(__DIR__) . '/include/ai_chat.php';
 </style>
 
 <div style="display:flex;justify-content:space-between;align-items:center;margin-bottom:12px;padding:0 2px;">
-  <span style="font-size:13px;font-weight:bold;color:#888;text-transform:uppercase;letter-spacing:.06em;">Arrs</span>
+  <span style="font-size:13px;font-weight:bold;color:#888;text-transform:uppercase;letter-spacing:.06em;">Media Stack</span>
   <span style="font-size:11px;color:#3a3a3a;" id="vv-arrs-ts"></span>
 </div>
 
@@ -150,7 +150,11 @@ require_once dirname(__DIR__) . '/include/ai_chat.php';
 // The conf sections this page is about, drawn by the shared renderer. They were reachable
 // only from the Settings tab's catch-all, which is a long way to go for a setting named
 // after the page you are already looking at.
-vv_conf_ui_card('vv-cf-arrs', 'arr|sonarr|radarr|lidarr', 'Arr settings');
+//
+// The match mirrors VV_UI_SECTION_SURFACES in confform.php and has to keep mirroring it: that
+// constant is what tells the assistant where to send someone, and this is what the page actually
+// draws. The two disagreeing means being given directions to a card that is not there.
+vv_conf_ui_card('vv-cf-arrs', 'arr|sonarr|radarr|lidarr|media|play state|emby|jellyfin|plex', 'Media settings');
 ?>
 <script>
 (function() {