3b1a35b7f2
Add OpenID Connect as an alternative login method. Users can sign in via an external identity provider (e.g., Authentik, Keycloak, Google). - OIDC settings configured in admin UI (discovery URL, client ID/secret, redirect URI, button label, enable/disable toggle) - PKCE-based authorization code flow with state and nonce validation - Admin can manually link any user's OIDC identity (sub/issuer fields) - Self-service linking: logged-in users can link/unlink their own account - SSO button conditionally shown on login page when OIDC is enabled - Username in header now clickable to open profile for all users - Callback errors/success communicated via URL hash fragments