[catsika]

What

Adds Client.DeleteKey(DeleteKeyParams) (*DeleteKeyResponse, error), typed and implemented like BlockKey, and re-exported from the deprecated /src package.

Contract

DELETE /key with Authorization: Bearer <admin key> and JSON body { "productId", "licenseKey" }. The license key goes in the body, never the URL. 200 returns { "message": "Key deleted", "code": 0 }. 404 returns { "message": "Invalid license key", "code": 1 } as an *ApiError. Needs an admin key or the license:delete permission.

No HTTP helper change: handleRequest already sends a JSON body for any method.

Tests

• New contract tests TestDeleteKey* (mock server) check the method, path, JSON body, that the key is not in the URL, the auth header, and that 200 and 404 both parse. Added to the CI -run filter.
• The CI consumer build now compiles DeleteKey through both import paths.
• The live test deletes the node-locked key, then checks that looking it up returns 404. Cleanup now deletes both created keys (best effort, retrying on 429) instead of blocking them, so the shared test workspace stops filling up.
• Ran locally: gofmt -l . (clean), go vet ./..., go test ./... all pass. The live test skips without secrets.