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>

tests/Service/Access/RoleServiceTest.php

@@ -66,6 +66,41 @@ class RoleServiceTest extends TestCase
         $this->assertTrue($result['ok']);
         $this->assertSame('uuid-42', $result['uuid']);
         $this->assertSame(42, $result['id']);
+        $this->assertEmpty($result['warnings']);
+    }
+
+    public function testCreateFromAdminReturnsDuplicateCodeAsWarning(): void
+    {
+        $this->roleRepo
+            ->expects($this->any())
+            ->method('existsByCode')
+            ->with('DUPE', 0)
+            ->willReturn(true);
+
+        $this->roleRepo
+            ->expects($this->any())
+            ->method('create')
+            ->willReturn(50);
+
+        $this->roleRepo
+            ->expects($this->any())
+            ->method('find')
+            ->with(50)
+            ->willReturn(['id' => 50, 'uuid' => 'uuid-50', 'description' => 'Dupe Role']);
+
+        $this->auditService
+            ->expects($this->once())
+            ->method('record');
+
+        $result = $this->service->createFromAdmin([
+            'description' => 'Dupe Role',
+            'code' => 'DUPE',
+            'active' => 1,
+        ], 1);
+
+        $this->assertTrue($result['ok']);
+        $this->assertNotEmpty($result['warnings']);
+        $this->assertEmpty($result['errors'] ?? []);
     }
 
     public function testCreateFromAdminRejectsEmptyDescription(): void
@@ -184,7 +219,7 @@ class RoleServiceTest extends TestCase
         $this->assertTrue($result['ok']);
     }
 
-    public function testUpdateFromAdminRejectsDuplicateCode(): void
+    public function testUpdateFromAdminReturnsDuplicateCodeAsWarning(): void
     {
         $this->roleRepo
             ->expects($this->once())
@@ -193,17 +228,30 @@ class RoleServiceTest extends TestCase
             ->willReturn(true);
 
         $this->roleRepo
-            ->expects($this->never())
-            ->method('update');
+            ->expects($this->once())
+            ->method('find')
+            ->with(10)
+            ->willReturn(['id' => 10, 'uuid' => 'uuid-10', 'active' => 1]);
+
+        $this->roleRepo
+            ->expects($this->once())
+            ->method('update')
+            ->with(10, $this->anything())
+            ->willReturn(true);
+
+        $this->auditService
+            ->expects($this->once())
+            ->method('record');
 
         $result = $this->service->updateFromAdmin(10, [
             'description' => 'Manager',
             'code' => 'ADMIN',
             'active' => 1,
-        ]);
+        ], 5);
 
-        $this->assertFalse($result['ok']);
-        $this->assertNotEmpty($result['errors']);
+        $this->assertTrue($result['ok']);
+        $this->assertNotEmpty($result['warnings']);
+        $this->assertEmpty($result['errors'] ?? []);
     }
 
     public function testUpdateFromAdminReturnsErrorWhenRepositoryUpdateFails(): void