Clarify delete cascade in API notes

docs/api-automation.md

@@ -33,4 +33,4 @@ level, and a server key has no user, so `/api/me` and other per-user routes refu
 - Keys are all-powerful within their scope (no read-only or per-resource scopes), and have no expiry.
 - `PUT` on ports replaces the whole object; omitted fields reset.
 - Site tokens are returned on create and, for admins, in `state`.
-- Deleting an edge/site does not check for ports that use it (the server cleans up or refuses; clients should order deletes).
+- Deleting an edge or site cascades silently (its ports and domains go with it, as do ports left with no target), so Terraform plans should not rely on dependent resources surviving.