feat(admin): Add user management and upgrade to module permission system

Features - User Management (Phase 4.1):
- Database: Add user_modules table for fine-grained module permissions
- Database: Add 4 user permissions (view/create/edit/delete) to role_permissions
- Backend: UserService (780 lines) - CRUD with tenant isolation
- Backend: UserController + UserRoutes (648 lines) - 13 API endpoints
- Backend: Batch import users from Excel
- Frontend: UserListPage (412 lines) - list/filter/search/pagination
- Frontend: UserFormPage (341 lines) - create/edit with module config
- Frontend: UserDetailPage (393 lines) - details/tenant/module management
- Frontend: 3 modal components (592 lines) - import/assign/configure
- API: GET/POST/PUT/DELETE /api/admin/users/* endpoints

Architecture Upgrade - Module Permission System:
- Backend: Add getUserModules() method in auth.service
- Backend: Login API returns modules array in user object
- Frontend: AuthContext adds hasModule() method
- Frontend: Navigation filters modules based on user.modules
- Frontend: RouteGuard checks requiredModule instead of requiredVersion
- Frontend: Remove deprecated version-based permission system
- UX: Only show accessible modules in navigation (clean UI)
- UX: Smart redirect after login (avoid 403 for regular users)

Fixes:
- Fix UTF-8 encoding corruption in ~100 docs files
- Fix pageSize type conversion in userService (String to Number)
- Fix authUser undefined error in TopNavigation
- Fix login redirect logic with role-based access check
- Update Git commit guidelines v1.2 with UTF-8 safety rules

Database Changes:
- CREATE TABLE user_modules (user_id, tenant_id, module_code, is_enabled)
- ADD UNIQUE CONSTRAINT (user_id, tenant_id, module_code)
- INSERT 4 permissions + role assignments
- UPDATE PUBLIC tenant with 8 module subscriptions

Technical:
- Backend: 5 new files (~2400 lines)
- Frontend: 10 new files (~2500 lines)
- Docs: 1 development record + 2 status updates + 1 guideline update
- Total: ~4900 lines of code

Status: User management 100% complete, module permission system operational

backend/src/index.ts

@@ -98,9 +98,11 @@ logger.info('✅ Prompt管理路由已注册: /api/admin/prompts');
 // 【运营管理】租户管理模块
 // ============================================
 import { tenantRoutes, moduleRoutes } from './modules/admin/routes/tenantRoutes.js';
+import { userRoutes } from './modules/admin/routes/userRoutes.js';
 await fastify.register(tenantRoutes, { prefix: '/api/admin/tenants' });
 await fastify.register(moduleRoutes, { prefix: '/api/admin/modules' });
-logger.info('✅ 租户管理路由已注册: /api/admin/tenants, /api/admin/modules');
+await fastify.register(userRoutes, { prefix: '/api/admin/users' });
+logger.info('✅ 运营管理路由已注册: /api/admin/tenants, /api/admin/modules, /api/admin/users');
 
 // ============================================
 // 【临时】平台基础设施测试API