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/package-lock.json

@@ -44,6 +44,7 @@
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         "@types/jsonwebtoken": "^9.0.7",
         "@types/node": "^24.7.1",
+        "@types/uuid": "^10.0.0",
         "@types/winston": "^2.4.4",
         "@types/xml2js": "^0.4.14",
         "better-sqlite3": "^12.4.6",
@@ -1098,6 +1099,13 @@
       "license": "MIT",
       "optional": true
     },
+    "node_modules/@types/uuid": {
+      "version": "10.0.0",
+      "resolved": "https://registry.npmmirror.com/@types/uuid/-/uuid-10.0.0.tgz",
+      "integrity": "sha512-7gqG38EyHgyP1S+7+xomFtL+ZNHcKv6DwNaCZmJmo1vgMugyF3TCnXVg4t1uk89mLNwnLtnY3TpOpCOyp1/xHQ==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@types/winston": {
       "version": "2.4.4",
       "resolved": "https://registry.npmmirror.com/@types/winston/-/winston-2.4.4.tgz",