### Redeem a card over the counter

`POST /api/v1/admin/cards/redeem-otc`

The same operation as the subscriber-facing redeem, with one difference: the acting manager is recorded as the reseller, so the redemption snapshots what they paid against what they charged. Without that, per-reseller pricing never resolves and every redemption records face value on both sides.

- Authentication: manager session (JWT) or API token
- Permission: `prm_cards_verify` (Verify / redeem cards)
- Risk: write
- Rate limit bucket: `card_redeem`
- Idempotent on `request_id`: retrying with the same id returns the original result

#### Parameters

| Name | In | Type | Required | Description |
| --- | --- | --- | --- | --- |
| `code` | body | string | yes | The plaintext card code. |
| `user_id` | body | integer | yes | The subscriber to credit. |
| `request_id` | body | string | yes | Idempotency key. |

#### Errors

| Code | Status | When |
| --- | --- | --- |
| `ERR_NOT_FOUND` | 404 | unknown code, or a card or subscriber outside the caller's authority |
| `ERR_CONFLICT` | 409 | already redeemed, or a request_id bound to another card |