💡 [FEATURE] - Add error callback hook in validateForm config

[isonnymichael]

Summary

Expose a hook so developers can run custom logic when validation fails on a field (e.g., analytics, logging, accessibility alerts).

Basic Example

validateForm('my-form', {
  onError: ({ input, message }) => {
    console.warn(`Error on ${input.name}: ${message}`);
  }
});

• onError is optional
• Invoked whenever a validation error is triggered
• Callback receives input and message
• Fully backward-compatible

Additional context

No response