* inbounds: surface form validation errors
React Hook Form validation previously returned early without showing why an inbound save was blocked. Report the first field error and switch to the corresponding form tab so operators can correct it.
* Fix inbound form tab error navigation
Improve react-hook-form error traversal so validation stops on real `FieldError` leaves (detected by `type`) instead of any object with a `message`. This makes Save reliably jump to the tab containing the first invalid field and show the specific error, avoiding the previous generic/ambiguous invalid-state handling.
---------
Co-authored-by: sonic <sonic@linux.do>
