Revert "ServerStatsService を無効化 (#91)"

This reverts commit b4f720cab6.

packages/backend/src/boot/common.ts

@@ -22,7 +22,7 @@ export async function server() {
 		app.get(ChartManagementService).start();
 		app.get(JanitorService).start();
 		app.get(QueueStatsService).start();
-		// app.get(ServerStatsService).start();
+		app.get(ServerStatsService).start();
 	}
 
 	return app;