- Use proper cryptographic challenge generation
- Add HMAC-SHA256 signatures for challenge verification
- Replace test signatures with real cryptographic signatures
- This should fix the verification failures
- Add GetAltchaChallenge method to both auth and admin handlers
- Simple implementation returning test challenge data
- This should fix the route registration issue
- Add ALTCHA service with challenge generation and verification
- Update auth and admin handlers to use ALTCHA tokens
- Replace Turnstile widget with ALTCHA widget in Flutter app
- Update admin frontend to use ALTCHA token
- Add ALTCHA challenge endpoints for both auth and admin
- Maintain development bypass for testing
- Remove Turnstile dependencies from authentication flow
