feat(auth): enhance registration page with OAuth support for Google and GitHub

app/(auth)/register/page.tsx

@@ -2,5 +2,18 @@ import { isInviteCodeRequired } from '@/lib/feature-flags';
 import RegisterPageClient from './register-page-client';
 
 export default function RegisterPage() {
-  return <RegisterPageClient requireInviteCode={isInviteCodeRequired()} />;
+  const googleEnabled = Boolean(
+    process.env.GOOGLE_CLIENT_ID && process.env.GOOGLE_CLIENT_SECRET,
+  );
+  const githubEnabled = Boolean(
+    process.env.GITHUB_CLIENT_ID && process.env.GITHUB_CLIENT_SECRET,
+  );
+
+  return (
+    <RegisterPageClient
+      requireInviteCode={isInviteCodeRequired()}
+      googleEnabled={googleEnabled}
+      githubEnabled={githubEnabled}
+    />
+  );
 }

app/(auth)/register/register-page-client.tsx

@@ -4,12 +4,19 @@ import { useEffect, useMemo, useState } from 'react';
 import Link from 'next/link';
 import { useRouter, useSearchParams } from 'next/navigation';
 import { Video, Loader2, KeyRound, UserPlus } from 'lucide-react';
+import { signIn } from 'next-auth/react';
 import { Button } from '@/components/ui/button';
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card';
 import { Input } from '@/components/ui/input';
 import { Label } from '@/components/ui/label';
 
-export default function RegisterPageClient({ requireInviteCode }: { requireInviteCode: boolean }) {
+interface RegisterPageClientProps {
+  requireInviteCode: boolean;
+  googleEnabled: boolean;
+  githubEnabled: boolean;
+}
+
+export default function RegisterPageClient({ requireInviteCode, googleEnabled, githubEnabled }: RegisterPageClientProps) {
   const router = useRouter();
   const searchParams = useSearchParams();
   const invitationToken = useMemo(() => searchParams.get('invitationToken') || '', [searchParams]);
@@ -17,6 +24,7 @@ export default function RegisterPageClient({ requireInviteCode }: { requireInvit
   const isInvitationFlow = invitationToken.length > 0;
   const shouldShowInviteCode = requireInviteCode && !isInvitationFlow;
   const [isLoading, setIsLoading] = useState(false);
+  const [oauthLoading, setOauthLoading] = useState<string | null>(null);
   const [error, setError] = useState('');
   const [formData, setFormData] = useState({
     name: '',
@@ -87,6 +95,15 @@ export default function RegisterPageClient({ requireInviteCode }: { requireInvit
     }
   };
 
+  const handleOAuthSignUp = async (provider: string) => {
+    setOauthLoading(provider);
+    setError('');
+    await signIn(provider, { callbackUrl: '/dashboard' });
+  };
+
+  const hasOAuth = googleEnabled || githubEnabled;
+  const anyLoading = isLoading || oauthLoading !== null;
+
   return (
     <div className="min-h-screen flex items-center justify-center p-4 bg-background">
       <div className="w-full max-w-md">
@@ -106,6 +123,63 @@ export default function RegisterPageClient({ requireInviteCode }: { requireInvit
             </CardDescription>
           </CardHeader>
           <CardContent>
+            {/* OAuth Buttons */}
+            {hasOAuth && (
+              <div className="space-y-2 mb-4">
+                {googleEnabled && (
+                  <Button
+                    type="button"
+                    variant="outline"
+                    className="w-full"
+                    disabled={anyLoading}
+                    onClick={() => handleOAuthSignUp('google')}
+                  >
+                    {oauthLoading === 'google' ? (
+                      <Loader2 className="h-4 w-4 mr-2 animate-spin" />
+                    ) : (
+                      <svg className="h-4 w-4 mr-2" viewBox="0 0 24 24" aria-hidden="true">
+                        <path d="M22.56 12.25c0-.78-.07-1.53-.2-2.25H12v4.26h5.92c-.26 1.37-1.04 2.53-2.21 3.31v2.77h3.57c2.08-1.92 3.28-4.74 3.28-8.09z" fill="#4285F4" />
+                        <path d="M12 23c2.97 0 5.46-.98 7.28-2.66l-3.57-2.77c-.98.66-2.23 1.06-3.71 1.06-2.86 0-5.29-1.93-6.16-4.53H2.18v2.84C3.99 20.53 7.7 23 12 23z" fill="#34A853" />
+                        <path d="M5.84 14.09c-.22-.66-.35-1.36-.35-2.09s.13-1.43.35-2.09V7.07H2.18C1.43 8.55 1 10.22 1 12s.43 3.45 1.18 4.93l2.85-2.22.81-.62z" fill="#FBBC05" />
+                        <path d="M12 5.38c1.62 0 3.06.56 4.21 1.64l3.15-3.15C17.45 2.09 14.97 1 12 1 7.7 1 3.99 3.47 2.18 7.07l3.66 2.84c.87-2.6 3.3-4.53 6.16-4.53z" fill="#EA4335" />
+                      </svg>
+                    )}
+                    Continue with Google
+                  </Button>
+                )}
+                {githubEnabled && (
+                  <Button
+                    type="button"
+                    variant="outline"
+                    className="w-full"
+                    disabled={anyLoading}
+                    onClick={() => handleOAuthSignUp('github')}
+                  >
+                    {oauthLoading === 'github' ? (
+                      <Loader2 className="h-4 w-4 mr-2 animate-spin" />
+                    ) : (
+                      <svg className="h-4 w-4 mr-2" viewBox="0 0 24 24" aria-hidden="true" fill="currentColor">
+                        <path d="M12 2C6.477 2 2 6.484 2 12.017c0 4.425 2.865 8.18 6.839 9.504.5.092.682-.217.682-.483 0-.237-.008-.868-.013-1.703-2.782.605-3.369-1.343-3.369-1.343-.454-1.158-1.11-1.466-1.11-1.466-.908-.62.069-.608.069-.608 1.003.07 1.531 1.032 1.531 1.032.892 1.53 2.341 1.088 2.91.832.092-.647.35-1.088.636-1.338-2.22-.253-4.555-1.113-4.555-4.951 0-1.093.39-1.988 1.029-2.688-.103-.253-.446-1.272.098-2.65 0 0 .84-.27 2.75 1.026A9.564 9.564 0 0112 6.844c.85.004 1.705.115 2.504.337 1.909-1.296 2.747-1.027 2.747-1.027.546 1.379.202 2.398.1 2.651.64.7 1.028 1.595 1.028 2.688 0 3.848-2.339 4.695-4.566 4.943.359.309.678.92.678 1.855 0 1.338-.012 2.419-.012 2.747 0 .268.18.58.688.482A10.019 10.019 0 0022 12.017C22 6.484 17.522 2 12 2z" />
+                      </svg>
+                    )}
+                    Continue with GitHub
+                  </Button>
+                )}
+              </div>
+            )}
+
+            {/* Divider */}
+            {hasOAuth && (
+              <div className="relative mb-4">
+                <div className="absolute inset-0 flex items-center">
+                  <span className="w-full border-t" />
+                </div>
+                <div className="relative flex justify-center text-xs uppercase">
+                  <span className="bg-card px-2 text-muted-foreground">or continue with email</span>
+                </div>
+              </div>
+            )}
+
             <form onSubmit={handleRegister} className="space-y-4">
               {isInvitationFlow ? (
                 <div className="p-3 rounded-md bg-primary/10 text-sm">
@@ -202,7 +276,7 @@ export default function RegisterPageClient({ requireInviteCode }: { requireInvit
                 </div>
               )}
 
-              <Button type="submit" className="w-full" disabled={isLoading}>
+              <Button type="submit" className="w-full" disabled={anyLoading}>
                 {isLoading && <Loader2 className="h-4 w-4 mr-2 animate-spin" />}
                 Create Account
               </Button>