💡 [FEATURE] - Add support for custom validators via options

[isonnymichael]

Summary

Enable real-time validation by adding a validateOnBlur option so that inputs are validated as soon as they lose focus, not just on form submit.

Basic Example

validateForm('my-form', {
  validators: {
    username: (value) => value.length >= 6,
    age: (value) => Number(value) > 18
  }
});

• Custom validators can be provided as an object
• Validator functions receive input value
• If validation fails, show default or custom error

Additional context

No response