fix: admin UI review round 1 (S47) - Art labels, usage only on success, result fallback

- Art column: only lit/media-delete and lit/divi-delete say "löscht",
  lit/post-trash "Papierkorb", other destructive tools "überschreibt".
- ConnectionUsage records only responses with status < 400 (mcp-oauth answers
  auth failures with WP_REST_Response 401, not WP_Error).
- Log result column: translated "unbekannt" instead of the raw value.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

tests/Unit/Admin/LogListTableTest.php

@@ -218,6 +218,7 @@ final class LogListTableTest extends TestCase
 
         self::assertStringContainsString('dashicons-' . $icon, $html);
         self::assertStringContainsString($word, $html);
+        self::assertStringNotContainsString('error', $html);
     }
 
     /** @return list<list<string>> */
@@ -226,7 +227,7 @@ final class LogListTableTest extends TestCase
         return [
             ['ok', 'yes-alt', 'erfolgreich'],
             ['partial', 'warning', 'teilweise'],
-            ['error<b>', 'dismiss', 'error&lt;b&gt;'],
+            ['error<b>', 'dismiss', 'unbekannt'],
         ];
     }