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/create().php

@@ -26,6 +26,7 @@ if (!$decision->isAllowed()) {
 
 $errorBag = formErrors();
 $errors = [];
+$warnings = [];
 $form = [
     'description' => '',
     'code' => '',
@@ -42,7 +43,7 @@ if ($request->isMethod('POST') && !Session::checkCsrfToken()) {
     return;
 }
 
-if ($request->hasBody('description')) {
+if ($request->isMethod('POST')) {
     $dbSession = app(\MintyPHP\Repository\Support\DatabaseSessionRepository::class);
     $transactionStarted = false;
 
@@ -52,6 +53,7 @@ if ($request->hasBody('description')) {
 
         $result = app(\MintyPHP\Service\Access\RoleService::class)->createFromAdmin($request->bodyAll(), $currentUserId);
         $form = $result['form'] ?? $form;
+        $warnings = $result['warnings'] ?? [];
         $errorBag->merge($result['errors'] ?? []);
         $selectedPermissionIds = $request->body('permission_ids', $selectedPermissionIds);
         if (!is_array($selectedPermissionIds)) {
@@ -75,15 +77,24 @@ if ($request->hasBody('description')) {
 
             $action = (string) $request->body('action', 'create');
             if ($action === 'create_close') {
+                if ($warnings) {
+                    Flash::info(implode(' ', $warnings), $closeTarget, 'role_warning');
+                }
                 Flash::success('Role created', $closeTarget, 'role_created');
                 Router::redirect($closeTarget);
             } else {
                 $uuid = (string) ($result['uuid'] ?? '');
                 if ($uuid !== '') {
                     $target = requestPathWithReturnTarget("admin/roles/edit/{$uuid}", $returnTarget);
+                    if ($warnings) {
+                        Flash::info(implode(' ', $warnings), $target, 'role_warning');
+                    }
                     Flash::success('Role created', $target, 'role_created');
                     Router::redirect($target);
                 } else {
+                    if ($warnings) {
+                        Flash::info(implode(' ', $warnings), $closeTarget, 'role_warning');
+                    }
                     Flash::success('Role created', $closeTarget, 'role_created');
                     Router::redirect($closeTarget);
                 }