Remove internal notification caller tokens

backend/notifications/interface/proto/v1/interface.proto

@@ -3,13 +3,13 @@ package sxchnge.notifications.v1;
 option go_package = "git.sendico.io/tech/sxchnge/notifications/interface/notifications/v1;notificationsv1";
 import "google/protobuf/timestamp.proto";
 
-// Internal service: authenticate callers over TLS. Send durably queues work.
+// Internal service on the trusted private network; no caller authentication. Send durably queues work.
 service NotificationsService {
   rpc Send(SendRequest) returns (SendResponse);
   rpc Get(GetRequest) returns (GetResponse);
 }
 message SendRequest {
-  string idempotency_key = 1; // Required; scoped to authenticated caller, retained seven days.
+  string idempotency_key = 1; // Required; scoped to the product namespace, retained seven days.
   string user_id = 2; // Caller resolves and authorizes recipient ownership.
   string template_id = 3;
   string template_version = 4;