docs(integration): record SpaceGame pilot checkpoint (#21)

docs/integration/sdk-seams.md

@@ -70,6 +70,7 @@ thread and do not also call `NetManager.PollEvents()` during that period.
 ```csharp
 RendezvousNetListener networkEvents = new();
 NetManager gameplayNetwork = networkEvents.CreateManager();
+gameplayNetwork.ChannelsCount = 3; // set the game's required count before Start
 if (!gameplayNetwork.Start(gameplayPort))
 {
     throw new InvalidOperationException("Gameplay UDP socket could not start.");
@@ -85,6 +86,10 @@ using RendezvousHostCoordinator host = new(
 host.Poll(); // call each game frame while this coordinator owns polling
 ```
 
+LiteNetLib defaults to one QoS channel. Set `ChannelsCount` before `Start` when
+the game protocol uses additional channels; both peers must configure the same
+count. Rendezvous does not choose, remap, or reserve a gameplay channel.
+
 Register normal game callbacks on `networkEvents.GameplayEvents`. Rendezvous
 reserves only its authenticated direct requests and forwards other callbacks.
 The same socket sends host presence, punches through the mediator, establishes