fix: 仅向已握手连接推送并拆分调度循环

internal/app/message/submit.go

@@ -276,6 +276,9 @@ INSERT INTO messages(
 	if result.State == StateDispatched {
 		a.wakeReceivers(ctx, result.ID, senderID)
 	}
+	if result.State == StateScheduled {
+		a.NotifyDispatch()
+	}
 	return result, nil
 }