feat(invite-system): implement user invite functionality with registration mode control

src/pages/Register.jsx

@@ -1,12 +1,15 @@
 import { useState } from 'react';
-import { Link, useNavigate } from 'react-router-dom';
+import { Link, useNavigate, useSearchParams } from 'react-router-dom';
 import { useAuth } from '../contexts/AuthContext';
 import { useLanguage } from '../contexts/LanguageContext';
-import { Mail, Lock, User, ArrowRight, Loader2, CheckCircle } from 'lucide-react';
+import { useBranding } from '../contexts/BrandingContext';
+import { Mail, Lock, User, ArrowRight, Loader2, CheckCircle, ShieldAlert } from 'lucide-react';
 import BrandLogo from '../components/BrandLogo';
 import toast from 'react-hot-toast';
 
 export default function Register() {
+  const [searchParams] = useSearchParams();
+  const inviteToken = searchParams.get('invite') || '';
   const [username, setUsername] = useState('');
   const [displayName, setDisplayName] = useState('');
   const [email, setEmail] = useState('');
@@ -16,8 +19,12 @@ export default function Register() {
   const [needsVerification, setNeedsVerification] = useState(false);
   const { register } = useAuth();
   const { t } = useLanguage();
+  const { registrationMode } = useBranding();
   const navigate = useNavigate();
 
+  // Invite-only mode without a token → show blocked message
+  const isBlocked = registrationMode === 'invite' && !inviteToken;
+
   const handleSubmit = async (e) => {
     e.preventDefault();
 
@@ -33,7 +40,7 @@ export default function Register() {
 
     setLoading(true);
     try {
-      const result = await register(username, displayName, email, password);
+      const result = await register(username, displayName, email, password, inviteToken);
       if (result?.needsVerification) {
         setNeedsVerification(true);
         toast.success(t('auth.verificationSent'));
@@ -77,6 +84,15 @@ export default function Register() {
                 {t('auth.login')}
               </Link>
             </div>
+          ) : isBlocked ? (
+            <div className="text-center space-y-4">
+              <ShieldAlert size={48} className="mx-auto text-amber-400" />
+              <h2 className="text-2xl font-bold text-th-text">{t('auth.inviteOnly')}</h2>
+              <p className="text-th-text-s">{t('auth.inviteOnlyDesc')}</p>
+              <Link to="/login" className="btn-primary inline-flex items-center gap-2 mt-4">
+                {t('auth.login')}
+              </Link>
+            </div>
           ) : (
             <>
           <div className="mb-8">