Initial release: game-studio plugin for Claude Code

Repackaged from OpenAI's game-studio Codex plugin (MIT) for Claude Code.

Changes from upstream:
- Added .claude-plugin/plugin.json (Claude Code plugin manifest)
- Removed .codex-plugin/plugin.json (Codex CLI specific)
- Removed skills/*/agents/openai.yaml (Codex CLI specific)
- Added scripts/requirements.txt (Pillow dependency for sprite-pipeline)
- Added Chinese README with installation guide

references/rapier-integration-starter.md

@@ -0,0 +1,42 @@
+# Rapier Integration Starter
+
+Use this as the smallest canonical pattern for adding physics without letting it take over the whole runtime.
+
+## Vanilla Three.js
+
+```ts
+import RAPIER from "@dimforge/rapier3d-compat";
+
+await RAPIER.init();
+
+const world = new RAPIER.World({ x: 0, y: -9.81, z: 0 });
+const body = world.createRigidBody(RAPIER.RigidBodyDesc.dynamic().setTranslation(0, 2, 0));
+world.createCollider(RAPIER.ColliderDesc.cuboid(0.5, 0.5, 0.5), body);
+
+renderer.setAnimationLoop(() => {
+  world.step();
+  const p = body.translation();
+  mesh.position.set(p.x, p.y, p.z);
+  renderer.render(scene, camera);
+});
+```
+
+## React Three Fiber
+
+```tsx
+import { Physics, RigidBody } from "@react-three/rapier";
+
+<Physics gravity={[0, -9.81, 0]}>
+  <RigidBody colliders="cuboid">
+    <mesh>
+      <boxGeometry args={[1, 1, 1]} />
+      <meshStandardMaterial color="#3dd9b8" />
+    </mesh>
+  </RigidBody>
+</Physics>;
+```
+
+## Notes
+
+- Keep physics state synchronized through an explicit bridge.
+- Do not bury gameplay rules inside render or physics callbacks.