add generic stateful input streaming

packages/engine/src/time-travel.ts

@@ -877,6 +877,7 @@ function createSeededEngine<
     client: game.client,
     replication: game.replication,
     validateInput: game.validateInput,
+    ...(game.inputStream ? { inputStream: game.inputStream } : {}),
     codecs: game.codecs,
   };
   return new NetworkedAuthoritativeEngine(definition, serverOptions);
@@ -969,6 +970,15 @@ function cloneSimulationCheckpoint<
       playerId,
       packet: cloneInputPacket(game, packet),
     })),
+    inputStreamStates: checkpoint.inputStreamStates.map((stream) => ({
+      ...stream,
+      clientInput: game.codecs.input.decode(
+        game.codecs.input.encode(stream.clientInput),
+      ),
+      appliedInput: game.codecs.input.decode(
+        game.codecs.input.encode(stream.appliedInput),
+      ),
+    })),
     pendingEvents: [...checkpoint.pendingEvents],
   };
 }