feat(auth): LoginPage - fix credentials, fetch /auth/me after login

frontend/src/pages/LoginPage.tsx

@@ -1,10 +1,11 @@
 import { useState } from 'react';
+import { setToken, setSessionUser } from '../lib/session';
 
-type Props = { onLogin: (token: string) => void };
+type Props = { onLogin: () => void };
 
 export function LoginPage({ onLogin }: Props) {
   const [username, setUsername] = useState('admin');
-  const [password, setPassword] = useState('admin123');
+  const [password, setPassword] = useState('admin');
   const [error, setError] = useState('');
   const [loading, setLoading] = useState(false);
 
@@ -16,7 +17,7 @@ export function LoginPage({ onLogin }: Props) {
       const body = new URLSearchParams();
       body.set('username', username);
       body.set('password', password);
-      const res = await fetch('/auth/token', {
+      const res = await fetch('/backend/auth/token', {
         method: 'POST',
         headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
         body: body.toString(),
@@ -25,8 +26,13 @@ export function LoginPage({ onLogin }: Props) {
         const data = await res.json().catch(() => null);
         throw new Error(data?.detail ?? 'Login fallito');
       }
-      const data = await res.json();
-      onLogin(data.access_token);
+      const { access_token } = await res.json();
+      setToken(access_token);
+      const meRes = await fetch('/backend/auth/me', {
+        headers: { Authorization: `Bearer ${access_token}` },
+      });
+      if (meRes.ok) setSessionUser(await meRes.json());
+      onLogin();
     } catch (err) {
       setError(err instanceof Error ? err.message : 'Login fallito');
     } finally {
@@ -49,7 +55,6 @@ export function LoginPage({ onLogin }: Props) {
             Password
             <input type="password" value={password} onChange={(e) => setPassword(e.target.value)} autoComplete="current-password" />
           </label>
-          <p className="login-hint">Credenziali demo: admin / admin123 oppure viewer / viewer123</p>
           {error && <p className="login-error">{error}</p>}
           <button type="submit" disabled={loading}>{loading ? 'Accesso...' : 'Entra'}</button>
         </form>