refactor(audit): extract audit domain into self-contained module

Move the entire audit subsystem (system audit, API audit, import audit,
user lifecycle audit, frontend telemetry) from core into modules/audit/.

Core decoupling via interface-based injection:
- AuditRecorderInterface replaces SystemAuditService in 10+ core services
- UserLifecycleAuditInterface / ImportAuditInterface for specialized flows
- NullAuditRecorder fallback when audit module is disabled
- ApiBootstrap/ApiResponse use null-safe callable resolvers

Module structure (modules/audit/):
- Manifest with routes, permissions, scheduler jobs, authorization policy
- 9 services, 8 repositories, 6 domain enums, 4 job handlers
- 33 page files, 4 JS files, 8 test files, migration scripts, i18n

Core cleanup:
- OperationsAuthorizationPolicy, UiCapabilityMap, PermissionService
  surgically cleaned of audit-specific constants
- Sidebar template cleared of hardcoded audit navigation
- AuditModuleIsolationContractTest ensures no future core→module coupling

All quality gates pass: 1346 tests (19,276 assertions), PHPStan level 5
clean, architecture contracts verified.

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

modules/audit/pages/admin/import-audit/purge().php

@@ -0,0 +1,24 @@
+<?php
+
+use MintyPHP\Module\Audit\Service\ImportAuditService;
+use MintyPHP\Router;
+use MintyPHP\Session;
+use MintyPHP\Support\Flash;
+use MintyPHP\Support\Guard;
+
+Guard::requireLogin();
+Guard::requireAbility(\MintyPHP\Service\Access\SettingsAuthorizationPolicy::ABILITY_ADMIN_SETTINGS_UPDATE);
+
+if (strtoupper((string) (requestInput()->method())) !== 'POST') {
+    Router::redirect('admin/import-audit');
+}
+$errorBag = formErrors();
+if (!Session::checkCsrfToken()) {
+    $errorBag->addGlobal(t('Form expired, please try again'));
+    flashFormErrors($errorBag, 'admin/import-audit', 'import_audit');
+    Router::redirect('admin/import-audit');
+}
+
+$deleted = app(ImportAuditService::class)->purgeExpired();
+Flash::success(sprintf(t('%d import audit entries purged'), $deleted), 'admin/import-audit', 'import_audit_purged');
+Router::redirect('admin/import-audit');