# Functions
CheckPassword compares the stored hash with the hashed combination of the given password and salt.
GenerateResetToken generates a 6-digit numerical reset token.
GenerateToken generates a JWT token for a user.
GenSalt generates a random salt for password hashing.
HashPassword hashes the password using the provided salt.
IsValidEmail checks if the provided email is valid.
SendResetTokenEmail sends the reset token to the user's email address.
SendResponse creates and sends a standardized JSON response.
VerifyToken verifies a JWT token and returns the user ID if the token is valid.
# Structs
APIResponse is a struct for a standardized API response.