Backend:
- New AUTH_PASSWORD_ENABLED flag (default true). When false, email/password
registration and login return 403; the server enforces OIDC-only login.
- New OIDC_GENERIC_DISPLAY_NAME so the app can show 'Authentik'/'Keycloak'
instead of a generic 'OIDC' label.
- New public endpoint GET /api/config returns which auth methods the
server offers (password_enabled + per-provider OIDC capabilities).
No auth required, so the login screen can query it before logging in.
- .env.example and docker-compose.yml expose the new env vars.
App:
- DTOs + MitbringslApi.getServerConfig() for /api/config.
- AuthViewModel: new 'connect' flow. The user enters the server URL,
taps 'Verbinden', and the app fetches /api/config. The returned
ServerAuthConfig drives which login options are shown:
* password-only -> email/password form
* OIDC-only -> OIDC token form
* both -> toggle between the two
If the server offers no method, a clear error is shown.
- AuthScreen: split into ConnectView (server URL) and LoginView (the
login form matching the server's capabilities). The mode toggle only
appears when the server offers more than one method.
