- 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>