fix: null display name, settings scrollbar, redundant passkey offer

- Profile API returns empty string instead of "null" when Logto user
  has no display name set (String.valueOf(null) → "null" bug).
- SettingsPage: add overflowY auto + flex 1 so content scrolls within
  the AppShell layout (which uses overflow: hidden).
- Remove redundant passkey offer from onboarding page — passkey
  enrollment now happens during sign-in via the Experience API.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/pages/OnboardingPage.tsx

@@ -20,7 +20,6 @@ export function OnboardingPage() {
   const [error, setError] = useState<string | null>(null);
   const [slugAvailable, setSlugAvailable] = useState<boolean | null>(null);
   const [checkingSlug, setCheckingSlug] = useState(false);
-  const [showPasskeyOffer, setShowPasskeyOffer] = useState(false);
   const debounceRef = useRef<ReturnType<typeof setTimeout>>(undefined);
 
   const slug = toSlug(name);
@@ -51,17 +50,6 @@ export function OnboardingPage() {
     setLoading(true);
     try {
       await api.post<TenantResponse>('/onboarding/tenant', { name, slug });
-      // Check if passkeys are enabled in vendor policy
-      try {
-        const config = await fetch('/platform/api/config').then(r => r.json());
-        if (config.vendorAuthPolicy?.passkeyEnabled) {
-          setShowPasskeyOffer(true);
-          setLoading(false);
-          return; // Don't redirect yet
-        }
-      } catch {
-        // Ignore — proceed without passkey offer
-      }
       // Tenant created — force a fresh OIDC sign-in so the Logto SDK gets
       // new tokens that include the org membership just created. The existing
       // Logto session cookie means the user won't see a login form — Logto
@@ -78,34 +66,6 @@ export function OnboardingPage() {
     }
   }
 
-  async function handleSkipPasskey() {
-    await signIn(`${window.location.origin}/platform/callback`);
-  }
-
-  if (showPasskeyOffer) {
-    return (
-      <div className={styles.page}>
-        <div className={styles.wrapper}>
-          <Card className={styles.card}>
-            <div className={styles.inner}>
-              <div style={{ textAlign: 'center' }}>
-                <h2 style={{ margin: '16px 0 8px' }}>Secure your account</h2>
-                <p style={{ color: 'var(--text-muted)', marginBottom: 24 }}>
-                  Add a passkey to sign in faster with your fingerprint, face, or security key.
-                </p>
-              </div>
-              <div style={{ display: 'flex', flexDirection: 'column', gap: 12 }}>
-                <Button variant="secondary" onClick={handleSkipPasskey}>
-                  Set up later
-                </Button>
-              </div>
-            </div>
-          </Card>
-        </div>
-      </div>
-    );
-  }
-
   return (
     <div className={styles.page}>
       <div className={styles.wrapper}>

ui/src/pages/tenant/SettingsPage.tsx

@@ -212,7 +212,7 @@ export function SettingsPage() {
   }
 
   return (
-    <div style={{ padding: 24, display: 'flex', flexDirection: 'column', gap: 20 }}>
+    <div style={{ padding: 24, display: 'flex', flexDirection: 'column', gap: 20, overflowY: 'auto', flex: 1 }}>
       <h1 style={{ margin: 0, fontSize: '1.25rem', fontWeight: 600 }}>Settings</h1>
       <PasskeyNudgeBanner />