Add privilege management system with related migrations and guards

- Introduced a new `PrivilegesModule` to manage user privileges and access control.
- Added `RequirePrivilege` decorator to enforce privilege checks on controller handlers.
- Implemented `PrivilegesGuard` to handle authorization based on user privileges.
- Created database migrations for `privileges`, `privilege_keys`, and `privilege_details` tables.
- Updated user model to include `is_superadmin` field for enhanced access control.
- Added unit tests for the new privileges functionality and guards to ensure correct behavior.

src/modules/users/users.service.spec.ts

@@ -1,6 +1,7 @@
 import { ConflictException } from '@nestjs/common';
 import { Test, TestingModule } from '@nestjs/testing';
 import { DateTime } from '../../common/value-objects/date-time/date-time';
+import { PrivilegesService } from '../privileges/privileges.service';
 import type { User } from './user';
 import { UsersRepository } from './users.repository';
 import { UsersService } from './users.service';
@@ -8,7 +9,13 @@ import { UsersService } from './users.service';
 describe('UsersService', () => {
   let service: UsersService;
   let repository: jest.Mocked<
-    Pick<UsersRepository, 'findById' | 'findByUsername' | 'create'>
+    Pick<
+      UsersRepository,
+      'findById' | 'findByUsername' | 'create' | 'updatePrivilegeId'
+    >
+  >;
+  let privilegesService: jest.Mocked<
+    Pick<PrivilegesService, 'findPrivilegeSummary'>
   >;
 
   const now = DateTime.fromUnixMs(1_700_000_000_000);
@@ -16,6 +23,8 @@ describe('UsersService', () => {
     id: 'user-1',
     username: 'alice',
     passwordHash: 'hashed',
+    privilegeId: null,
+    isSuperadmin: false,
     createdAt: now,
     updatedAt: now,
   };
@@ -25,12 +34,17 @@ describe('UsersService', () => {
       findById: jest.fn(),
       findByUsername: jest.fn(),
       create: jest.fn(),
+      updatePrivilegeId: jest.fn(),
+    };
+    privilegesService = {
+      findPrivilegeSummary: jest.fn(),
     };
 
     const moduleRef: TestingModule = await Test.createTestingModule({
       providers: [
         UsersService,
         { provide: UsersRepository, useValue: repository },
+        { provide: PrivilegesService, useValue: privilegesService },
       ],
     }).compile();
 
@@ -68,4 +82,21 @@ describe('UsersService', () => {
     repository.findByUsername.mockResolvedValue(sampleUser);
     await expect(service.findByUsername('Alice')).resolves.toEqual(sampleUser);
   });
+
+  it('assignPrivilege validates privilege exists', async () => {
+    repository.findById.mockResolvedValue(sampleUser);
+    privilegesService.findPrivilegeSummary.mockResolvedValue({
+      id: 'priv-1',
+      name: 'Admin',
+      code: 'ADMIN',
+      status: 'active',
+    });
+    repository.updatePrivilegeId.mockResolvedValue({
+      ...sampleUser,
+      privilegeId: 'priv-1',
+    });
+
+    const result = await service.assignPrivilege('user-1', 'priv-1');
+    expect(result.privilegeId).toBe('priv-1');
+  });
 });