Transaction reversal errors and refunding status

When a transaction reversal cannot complete or the refund step fails, you get a clear error code and message instead of an unexplained failure or an unexpected status. Reversals that trigger refund work now report REFUNDING while the refund is in progress, so status polling matches what your integration expects during multi-step reversals.

• Failed reversals return structured error details with a code and message, including provider response context when available, so you can see why the reversal could not finish.
• Invalid parent transactions, refund amounts above the original charge, and missing refund mappings return specific errors instead of failing without explanation.