Fetch Single VTU Transaction

Fetch one VTU purchase by its transaction ID.

Path: id (string, required) — the transactionId returned by a purchase endpoint. Use this to poll a PENDING purchase. Returns the full stored record (minus provider references/raw response), with the category and product. Note: the utility token is not included here — it is only returned in the purchase response.

Error format: body validation failures (Joi) return { "status": "error", "message": "Validation error", "details": [ ... ] }; all other errors return { "success": false, "message": "..." }. Money fields (amount, fee) are Prisma Decimals and are serialized as strings (e.g. "1000").