fix: media usage check fails closed on database errors; refused deletes checked for partial state

MediaUsageFinder treats a failed query (null result or last_error) as a possible
usage and an incomplete scan, so media-delete refuses without force. A refused
wp_delete_attachment() is write_failed only when the attachment is intact,
otherwise partial_write. media-update: re-read hint on write_failed, normalized
ids in failures, documented lock resolution and kses on restore.

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

src/Integrations/Media/MediaDeleteAbility.php

@@ -10,6 +10,7 @@ use LIT\MCP\Abilities\FollowUp;
 use LIT\MCP\Abilities\ToolResult;
 use LIT\MCP\ChangeLog\ChangeLog;
 use WP_Error;
+use WP_Post;
 
 /**
  * lit/media-delete: deletes one attachment after confirmation. WordPress has no media trash by
@@ -123,8 +124,9 @@ final class MediaDeleteAbility implements Ability
             );
         }
 
+        $file = (string) get_post_meta($id, '_wp_attached_file', true);
         if (! wp_delete_attachment($id, false)) {
-            return Errors::writeFailed(sprintf('WordPress hat das Löschen von Medium %d abgelehnt.', $id));
+            return $this->refused($id, $title, $file);
         }
 
         $warnings = [];
@@ -145,6 +147,40 @@ final class MediaDeleteAbility implements Ability
             ->toArray();
     }
 
+    /**
+     * wp_delete_attachment() returned false/null. It deletes meta, terms and the row before the
+     * files, so a failure can leave half a deletion: only an attachment that is still there with
+     * its file reference intact counts as "nothing deleted".
+     */
+    private function refused(int $id, string $title, string $file): WP_Error
+    {
+        $reason = sprintf('WordPress hat das Löschen von Medium %d abgelehnt.', $id);
+        $current = get_post($id);
+        $intact = $current instanceof WP_Post
+            && $current->post_type === 'attachment'
+            && (string) get_post_meta($id, '_wp_attached_file', true) === $file;
+        if ($intact) {
+            return Errors::writeFailed($reason);
+        }
+
+        $this->log->recordPartial(
+            $this->name(),
+            'attachment',
+            (string) $id,
+            sprintf('Medium "%s": Löschen nur teilweise ausgeführt', $title)
+        );
+
+        return Errors::partialWrite(
+            $reason,
+            null,
+            null,
+            sprintf('Medium %d ist möglicherweise teilweise gelöscht (Daten oder Dateien fehlen).', $id),
+            'Den Aufruf nicht einfach wiederholen. Das Medium mit lit/media-get bzw. in der WordPress-Mediathek '
+                . 'prüfen und dem Nutzer Bescheid geben.',
+            ['attachment_id' => $id]
+        );
+    }
+
     /** @param list<array<string, mixed>> $usages */
     private function question(int $id, string $title, bool $trash, array $usages): string
     {