feat: My Settings — password change (local only), timezone, MFA, auth_provider field

- MySettingsPage: timezone, password change (local users), MFA setup/disable
- Password change hidden for federated users (auth_provider != local)
- Federated users see info message: "managed by Oracle IAM"
- Backend: auth_provider + oidc_subject columns in users table (migration)
- /users/me returns auth_provider field
- User interface updated with auth_provider
- i18n: 12 new keys (pt/en) for password change

frontend-react/src/api/endpoints/auth.ts

@@ -9,6 +9,7 @@ export interface User {
   email?: string;
   mfa_enabled?: boolean;
   timezone?: string;
+  auth_provider?: string;
 }
 
 export interface LoginResponse {