feat: batch media metadata updates and delete with usage check

lit/media-update validates the whole batch first (edit_post, lengths, optional
modified lock) and restores already written items when a write fails midway.
lit/media-delete requires confirm, refuses used media without force and
reports refused deletes as write_failed.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01At3V6SjwbMe6eMzVGW3Hs7

tests/Unit/Integrations/Media/MediaIntegrationTest.php

@@ -22,6 +22,8 @@ final class MediaIntegrationTest extends TestCase
         'lit/media-upload-from-url',
         'lit/media-upload',
         'lit/media-download',
+        'lit/media-update',
+        'lit/media-delete',
     ];
 
     public function testProvidesTheMediaAbilities(): void