refactor: fix 7 CRUD system inconsistencies for robustness and maintainability

- Add user-assignment dependency check to DepartmentService.deleteByUuid (409 when users assigned)
- Standardize POST detection to isMethod('POST') in 10 create/edit actions
- Align RoleService code uniqueness to warning pattern (matching departments)
- Normalize repository create() return types from mixed to int|false (3 repos + 3 interfaces)
- Add JSON response branches to 4 non-user delete actions
- Document delete authorization ordering pattern
- Decompose AdminSettingsService.updateFromAdmin into domain-scoped private methods

Workflow: .agents/runs/CRUD-CONSISTENCY-001/
Reviewed by: Code Reviewer (pass), Security Reviewer (pass), Acceptance Tester (pass)
Quality gates: QG-001 PHPUnit pass, QG-002 PHPStan pass, QG-003 Architecture pass

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

pages/admin/roles/edit($id).php

@@ -44,6 +44,7 @@ app(\MintyPHP\Service\Audit\AuditMetadataEnricher::class)->enrich($role);
 
 $errorBag = formErrors();
 $errors = [];
+$warnings = [];
 $form = $role;
 $permissions = $permissionRepository->listActive();
 $selectedPermissionIds = $rolePermissionRepository->listPermissionIdsByRoleId($roleId);
@@ -58,7 +59,7 @@ if ($request->isMethod('POST') && !Session::checkCsrfToken()) {
     return;
 }
 
-if ($request->hasBody('description')) {
+if ($request->isMethod('POST')) {
     $submitDecision = $authorizationService->authorize(RoleAuthorizationPolicy::ABILITY_ADMIN_ROLES_EDIT_SUBMIT, [
         'actor_user_id' => $currentUserId,
         'target_role_id' => $roleId,
@@ -68,6 +69,7 @@ if ($request->hasBody('description')) {
     }
     $result = app(\MintyPHP\Service\Access\RoleService::class)->updateFromAdmin($roleId, $request->bodyAll(), $currentUserId);
     $form = $result['form'] ?? $form;
+    $warnings = $result['warnings'] ?? [];
     $errorBag->merge($result['errors'] ?? []);
     $selectedPermissionIds = $request->body('permission_ids', $selectedPermissionIds);
     if (!is_array($selectedPermissionIds)) {
@@ -108,9 +110,15 @@ if ($request->hasBody('description')) {
         if ($syncSucceeded) {
             $action = (string) $request->body('action', 'save');
             if ($action === 'save_close') {
+                if ($warnings) {
+                    Flash::info(implode(' ', $warnings), $closeTarget, 'role_warning');
+                }
                 Flash::success('Role updated', $closeTarget, 'role_updated');
                 Router::redirect($closeTarget);
             } else {
+                if ($warnings) {
+                    Flash::info(implode(' ', $warnings), $editTarget, 'role_warning');
+                }
                 Flash::success('Role updated', $editTarget, 'role_updated');
                 Router::redirect($editTarget);
             }