[wojt-janowski]

Summary

Adds a Validation page to the Mobile v4 docs under Digging Deeper, between Data Binding and Reactivity. It documents the ValidatesInput trait from NativePHP/mobile-air#614, as Simon asked there.

It covers:

• Adding the trait, with a complete screen and view example.
• rules() or a $rules property, plus messages() and validationAttributes().
• validate() vs validateOnly(), including using validateOnly() from an updated*() hook with .blur / .debounce, and the helpers addError(), resetValidation() and getErrorBag().
• Showing errors with @error, and driving a text input's is-error / supporting from $errors.
• Which handlers have their validation errors caught: view event handlers and native:model syncs are caught. Lifecycle hooks, #[On] / #[OnNative] listeners and #[Poll] methods still reach the error overlay. A callout covers the emit() case, where a parent's messages land in the child's bag.

It also notes that validateOnly() doesn't match wildcard rules yet, and that tests go through the same interaction path as a device.

The page is marked "since 4.7", the first mobile-air release with the trait.

Testing

• php artisan test --filter=Documentation: 8 passed, including the check that every docs page renders.
• Rendered the page locally and checked the sidebar entry, code blocks, @error examples and callouts.