forked from baron/baron-sso
- Add `ValidateLoginID` to enforce ID collision and security rules (prevents phone number collision, email format usage, and reserved words). - Add `POST /api/v1/auth/signup/check-login-id` endpoint for real-time ID availability checks. - Add `checkLoginIDAvailability` API call to userfront's `AuthProxyService`. - Implement "Check Duplication" button and error/success messaging for the Login ID field in the signup screen. - Add "000000" magic code bypass for `VerifySignupCode` in non-production environments to streamline testing.