Module validations 

validatable module — email format + password length checks on registration (the Devise validatable analogue). Gated at runtime by auth.modules.

Functions

validate_email

A conservative email format check (local@domain, a dot in the domain, no whitespace). Returns a AuthError::Validation on failure.

validate_password_length

Enforce a minimum password length.

validate_registration

Validate an email/password pair for registration when the validatable module is enabled. A no-op when auth state isn’t initialised (unit tests) or the module is disabled, so callers can invoke it unconditionally.