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/react-three-fiber-starter.md

@@ -0,0 +1,51 @@
+# React Three Fiber Starter
+
+Use this as the smallest canonical starting point for a React-hosted 3D scene.
+
+## Files
+
+```text
+src/
+  App.tsx
+```
+
+## `src/App.tsx`
+
+```tsx
+import { Canvas } from "@react-three/fiber";
+
+function Spinner() {
+  return (
+    <mesh rotation={[0.4, 0.6, 0]}>
+      <boxGeometry args={[1, 1, 1]} />
+      <meshStandardMaterial color="#3dd9b8" />
+    </mesh>
+  );
+}
+
+export default function App() {
+  return (
+    <div className="app-shell">
+      <Canvas camera={{ position: [0, 1.5, 4], fov: 60 }}>
+        <color attach="background" args={["#101418"]} />
+        <ambientLight intensity={0.7} />
+        <directionalLight position={[4, 6, 3]} intensity={1.2} />
+        <Spinner />
+      </Canvas>
+      <div className="hud">
+        <div className="objective-chip">Reach the lantern bridge.</div>
+        <div className="hint-pill">WASD to move. Hold mouse to look.</div>
+      </div>
+    </div>
+  );
+}
+```
+
+## Notes
+
+- Start here when the 3D scene lives inside an existing React app.
+- Keep the initial HUD sparse. One compact objective surface and one transient hint is usually enough for a first playable scaffold.
+- Put lore, notes, map, and settings behind drawers or modals instead of opening them all by default.
+- Add GLB loading with `gltf-loading-starter.md`.
+- Add physics with `rapier-integration-starter.md`.
+- Use `three-hud-layout-patterns.md` for low-chrome 3D overlay defaults.