get /v1/notifications/channels
List notification channels（不含 secrets/signing_secret）
Free (not billed).
Auth: Authorization: Bearer ac-… · billed per call (see Credits) — envelope {success,data,credit_cost} or {success:false,error}.
Responses
| Status | Description | Body |
|---|---|---|
200 | OK | application/json — object |
default | Error | application/json — ErrorResponse |