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>

tests/Service/Access/OperationsAuthorizationPolicyTest.php

@@ -110,20 +110,6 @@ class OperationsAuthorizationPolicyTest extends TestCase
         $this->assertForbiddenDecision($decision);
     }
 
-    public function testSystemAuditPurgeAllowedWithPermission(): void
-    {
-        $permissionService = $this->permissionGatewayAllowing([
-            3 => [PermissionService::SYSTEM_AUDIT_PURGE],
-        ]);
-
-        $policy = new OperationsAuthorizationPolicy($permissionService);
-        $decision = $policy->authorize(OperationsAuthorizationPolicy::ABILITY_ADMIN_SYSTEM_AUDIT_PURGE, [
-            'actor_user_id' => 3,
-        ]);
-
-        $this->assertTrue($decision->isAllowed());
-    }
-
     // --- authorize: authorizeUsersCreateCustomFields (requires TWO permissions) ---
 
     public function testUsersCreateCustomFieldsAllowedWithBothPermissions(): void