Publish on 'test' channel (index 3) by default (#10)

src/mesh/mesh.service.ts

@@ -71,9 +71,9 @@ export class MeshService implements OnModuleInit, OnModuleDestroy {
     process.env.MESH_RECONNECT_MS ?? '5000',
     10,
   );
-  // sends are pinned to the test channel ("testowy", index 2) on purpose — never the primary channel
+  // sends are pinned to the test channel ("test", index 3) on purpose — never the primary channel
   private readonly sendChannel = parseInt(
-    process.env.MESH_SEND_CHANNEL ?? '2',
+    process.env.MESH_SEND_CHANNEL ?? '3',
     10,
   );