fix(auth): redirect signed-in users away from /login and /register (#50)

src/app/login/page.tsx

@@ -5,6 +5,7 @@ import { useRouter } from 'next/navigation';
 import Link from 'next/link';
 import { Mail, Lock } from 'lucide-react';
 import { useAuth } from '@/lib/auth-context';
+import { useRedirectIfAuthenticated } from '@/lib/use-redirect-if-authenticated';
 import { ApiError } from '@/lib/api';
 import { FormError } from '@/components/form-error';
 import { AuthLayout } from '@/components/auth-layout';
@@ -18,6 +19,7 @@ export default function LoginPage() {
   const [password, setPassword] = useState('');
   const [error, setError] = useState<string | null>(null);
   const [submitting, setSubmitting] = useState(false);
+  const redirecting = useRedirectIfAuthenticated();
 
   async function handleSubmit(e: React.FormEvent) {
     e.preventDefault();
@@ -37,6 +39,9 @@ export default function LoginPage() {
     }
   }
 
+  // Signed-in users are sent to their dashboard instead of seeing the form (#50).
+  if (redirecting) return null;
+
   return (
     <AuthLayout title="Welcome back" subtitle="Log in to manage your tickets and organizations.">
       <form onSubmit={handleSubmit} className="flex flex-col gap-5">

src/app/register/page.tsx

@@ -5,6 +5,7 @@ import { useRouter } from 'next/navigation';
 import Link from 'next/link';
 import { User, Mail, Lock } from 'lucide-react';
 import { useAuth } from '@/lib/auth-context';
+import { useRedirectIfAuthenticated } from '@/lib/use-redirect-if-authenticated';
 import { ApiError } from '@/lib/api';
 import { FormError } from '@/components/form-error';
 import { AuthLayout } from '@/components/auth-layout';
@@ -19,6 +20,7 @@ export default function RegisterPage() {
   const [password, setPassword] = useState('');
   const [error, setError] = useState<string | null>(null);
   const [submitting, setSubmitting] = useState(false);
+  const redirecting = useRedirectIfAuthenticated();
 
   async function handleSubmit(e: React.FormEvent) {
     e.preventDefault();
@@ -38,6 +40,9 @@ export default function RegisterPage() {
     }
   }
 
+  // Signed-in users are sent to their dashboard instead of seeing the form (#50).
+  if (redirecting) return null;
+
   return (
     <AuthLayout
       title="Create your account"

src/lib/use-redirect-if-authenticated.ts

@@ -0,0 +1,27 @@
+'use client';
+
+import { useEffect } from 'react';
+import { useRouter } from 'next/navigation';
+import { useAuth } from './auth-context';
+
+/** Where a signed-in user lands by default (matches the post-login redirect). */
+export const DEFAULT_AUTHENTICATED_PATH = '/dashboard';
+
+/**
+ * Guest-only pages (/login, /register): once auth has finished loading, send
+ * a signed-in user to their default page with `router.replace`, so the auth
+ * form isn't left in history (#50).
+ *
+ * Returns true while the page should render nothing — auth still loading or a
+ * redirect in flight — so the form never flashes for a signed-in user.
+ */
+export function useRedirectIfAuthenticated(to: string = DEFAULT_AUTHENTICATED_PATH): boolean {
+  const { user, loading } = useAuth();
+  const router = useRouter();
+
+  useEffect(() => {
+    if (!loading && user) router.replace(to);
+  }, [loading, user, router, to]);
+
+  return loading || user !== null;
+}