fix(audit): harden module isolation and fix post-extraction drift

Fix 5 broken FQCN references (runtime errors) where core pages referenced
non-existent MintyPHP\Service\Audit\AuditMetadataEnricher and SystemAuditService.
Add AuditMetadataEnricherInterface with NullAuditMetadataEnricher fallback so
deactivating the audit module no longer crashes core edit pages.

Move audit search resources from core Search*Provider files into the module
via a new AuditSearchResourceProvider implementing the existing
SearchResourceProvider contract. Add module-specific purge permissions
(audit.api.purge, audit.imports.purge) replacing core ABILITY_ADMIN_SETTINGS_UPDATE.

Also fixes: session key prefix convention, hardcoded English string, $_SERVER
superglobal fallback, and manifest schema drift (i18n_path, group in ui_slots).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/Support/Search/SearchUiMetaProvider.php

@@ -13,8 +13,6 @@ class SearchUiMetaProvider
         'scheduled-jobs' => 'bi-calendar-check',
         'pages' => 'bi-file-text',
         'mail-log' => 'bi-envelope-paper',
-        'api-audit' => 'bi-shield-check',
-        'system-audit' => 'bi-journal-lock',
         'docs' => 'bi-journal-text',
     ];
 
@@ -27,8 +25,6 @@ class SearchUiMetaProvider
         'scheduled-jobs',
         'pages',
         'mail-log',
-        'api-audit',
-        'system-audit',
     ];
 
     public static function iconForKey(string $key): string
@@ -49,8 +45,6 @@ class SearchUiMetaProvider
             'scheduled-jobs' => lurl('admin/scheduled-jobs') . '?search=' . $encoded,
             'pages' => lurl(''),
             'mail-log' => lurl('admin/mail-log') . '?search=' . $encoded,
-            'api-audit' => lurl('admin/api-audit') . '?search=' . $encoded,
-            'system-audit' => lurl('admin/system-audit') . '?search=' . $encoded,
             default => lurl(''),
         };
     }