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/web-3d-asset-pipeline.md

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+# Web 3D Asset Pipeline
+
+This is the default 3D asset shipping guidance for the plugin.
+
+## Primary sources
+
+- [Blender glTF exporter manual](https://docs.blender.org/manual/en/latest/addons/import_export/scene_gltf2.html)
+- [glTF 2.0 specification](https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html)
+- [glTF Transform](https://gltf-transform.dev/)
+- [PlayCanvas supported formats](https://developer.playcanvas.com/user-manual/assets/supported-formats/) for a good reference on why GLB is the recommended runtime format in browser engines
+
+## Default output
+
+- Ship GLB when possible.
+- Use `.gltf` with external files only when the asset pipeline or delivery strategy genuinely needs that shape.
+
+## Recommended workflow
+
+1. Clean the source asset in the DCC tool.
+2. Export to GLB or glTF 2.0.
+3. Run glTF Transform for validation, pruning, deduplication, and size reduction.
+4. Apply the chosen geometry and texture compression strategy.
+5. Verify pivots, scale, collision assumptions, and hierarchy naming.
+6. Test the asset in the runtime before treating it as final.
+
+## Compression and optimization
+
+- Use Draco or Meshopt deliberately, not both by default.
+- Use KTX2 or BasisU when the runtime stack supports GPU-friendly compressed textures.
+- Keep texture resolution aligned with actual on-screen use.
+- Reuse materials and avoid unnecessary texture uniqueness.
+
+## Runtime checks
+
+- scale is consistent across assets
+- pivots match gameplay expectations
+- node names are stable
+- collision proxy needs are handled
+- animation clips and variants load correctly
+- memory and load time are reasonable for the scene
+
+## Starter patterns
+
+- `threejs-vanilla-starter.md`
+- `react-three-fiber-starter.md`
+- `gltf-loading-starter.md`
+- `rapier-integration-starter.md`