Add a mesh scope to the Streams card

Local stays the default and the cheap path; mesh asks each partner for its own
sessions over SSH, live rather than cached, because a stream is true for
minutes and a cached one would be confidently wrong about the only thing the
card exists to say.

Plugin/unraid/api/media.php

@@ -30,10 +30,22 @@
 // RESPONSE
 //   vv_media_sessions() verbatim — a flat list of normalised sessions across all servers
 //
+// REQUEST
+//   GET                 this host's sessions
+//   GET ?scope=mesh     every node's sessions, each row tagged with the host it is playing on
+//
+//   Local is the default and stays the cheap path: one call per configured media server here.
+//   Mesh adds one bounded SSH hop per partner and is only requested while the operator is looking
+//   at the mesh view, so a dashboard left open on the default costs exactly what it did before.
+//
 // DEPENDS ON
-//   include/media.php   vv_media_sessions()
+//   include/media.php   vv_media_sessions(), vv_media_sessions_mesh()
 // ═══════════════════════════════════════════════════════════════════════════════════════════════
 header('Content-Type: application/json');
 require_once dirname(__DIR__) . '/include/media.php';
 
-echo json_encode(vv_media_sessions());
+// Anything that is not the literal "mesh" is local. Fail-closed on the expensive path, matching
+// how every other toggle in this plugin reads its value.
+echo json_encode(($_GET['scope'] ?? '') === 'mesh'
+    ? vv_media_sessions_mesh()
+    : vv_media_sessions() + ['scope' => 'local']);