Add message queue agent (#6463)

* scaffold message queue agent

* adjust proto, add mq_agent

* add agent client implementation

* remove unused function

* agent publish server implementation

* adding agent

weed/pb/mq_pb/mq_broker_grpc.pb.go

@@ -1,8 +1,8 @@
 // Code generated by protoc-gen-go-grpc. DO NOT EDIT.
 // versions:
 // - protoc-gen-go-grpc v1.5.1
-// - protoc             v5.28.1
-// source: mq.proto
+// - protoc             v5.28.3
+// source: mq_broker.proto
 
 package mq_pb
 
@@ -589,5 +589,5 @@ var SeaweedMessaging_ServiceDesc = grpc.ServiceDesc{
 			ClientStreams: true,
 		},
 	},
-	Metadata: "mq.proto",
+	Metadata: "mq_broker.proto",
 }