ComparePassword compares a hashed password with the plaintext password.

HashPassword hashes a plaintext password using bcrypt.

NewPasswordValidationConfig creates a new PasswordValidationConfig with default values.

ValidateEmail checks if the email format is valid.

ValidatePassword checks if the password meets the minimum length and passes additional validations.

AddPasswordSpecialCharValidator checks if the password contains at least one special character.

AddPasswordStrengthValidator checks if the password contains at least one uppercase letter and one number.

PasswordValidationConfig holds the configuration for validating passwords.

PasswordValidator is an interface for custom password validation strategies.