feat: add whether to enable self registration toggle (#760)

* refactor(frontend): extract RegistrationDisabled as reusable component
- Create RegistrationDisabled component with i18n support
- Add registrationClosed and registrationClosedMessage translations
- Replace inline JSX in App.tsx with new component
- Improve code maintainability and reusability
- Add hover effect to back button for better UX
* fix(frontend): add registration toggle to LoginModal component
- Add useSystemConfig hook to LoginModal
- Conditionally render registration button based on registration_enabled config
- Ensures consistency with HeaderBar and LoginPage registration controls
- Completes registration toggle feature implementation across all entry points
* feat(frontend): add registration toggle UI support
- Add registration disabled page in App.tsx when registration is closed
- Hide registration link in LoginPage when registration is disabled
- Add registration_enabled field to SystemConfig interface
- Frontend conditionally shows/hides registration UI based on backend config
* feat: add registration toggle feature
Add system-level registration enable/disable control:
- Add registration_enabled config to system_config table (default: true)
- Add registration check in handleRegister API endpoint
- Expose registration_enabled status in /api/config endpoint
- Frontend can use this config to conditionally show/hide registration UI
This allows administrators to control user registration without code changes.
* fix(frontend): add registration toggle to HeaderBar and RegisterPage
- Add useSystemConfig hook and registrationEnabled check to HeaderBar
- Conditionally show/hide signup buttons in both desktop and mobile views
- Add registration check to RegisterPage to show RegistrationDisabled component
- This completes the registration toggle feature across all UI components
* test(frontend): add comprehensive unit tests for registration toggle feature
- Add RegistrationDisabled component tests (rendering, navigation, styling)
- Add registrationToggle logic tests (config handling, edge cases, multi-location consistency)
- Configure Vitest with jsdom environment for React component testing
- All 80 tests passing (9 new tests for RegistrationDisabled + 21 for toggle logic)

web/src/components/LoginPage.tsx

@@ -6,6 +6,7 @@ import { t } from '../i18n/translations'
 import { Eye, EyeOff } from 'lucide-react'
 import { Input } from './ui/input'
 import { toast } from 'sonner'
+import { useSystemConfig } from '../hooks/useSystemConfig'
 
 export function LoginPage() {
   const { language } = useLanguage()
@@ -21,6 +22,8 @@ export function LoginPage() {
   const [loading, setLoading] = useState(false)
   const [adminPassword, setAdminPassword] = useState('')
   const adminMode = false
+  const { config: systemConfig } = useSystemConfig()
+  const registrationEnabled = systemConfig?.registration_enabled !== false
 
   const handleAdminLogin = async (e: React.FormEvent) => {
     e.preventDefault()
@@ -313,7 +316,7 @@ export function LoginPage() {
         </div>
 
         {/* Register Link */}
-        {!adminMode && (
+        {!adminMode && registrationEnabled && (
           <div className="text-center mt-6">
             <p className="text-sm" style={{ color: 'var(--text-secondary)' }}>
               还没有账户？{' '}