- Add enablePasswordReset, enableRefreshTokenRotation, enableAuditLogging flags
- All flags default to false for backward compatibility
- Add getOptionalBoolean helper for parsing boolean env vars
- Update .env.example with feature flag documentation
- Add PasswordResetToken model for password reset flow
- Add RefreshToken model for token rotation tracking
- Add AuditLog model for security event logging
- All features disabled by default via feature flags
- Add User model with email, passwordHash, and name fields
- Add userId foreign key to Drawing and Collection models
- Create initial migration for user authentication
Matteo