Initial public release: cc-3-8-x-mcp

Cocos Creator 3.8.x MCP bridge extension with a built-in offline CLI.

Components:
- Editor extension: in-process MCP server exposing scene / asset-db /
  preview / local / editor-process-control tools
- stdio router: aggregates multiple editor instances on one machine,
  with shortName dedup
- offline CLI (cocos-mcp-cli): headless prefab read/write + a wrapper
  around the Cocos CLI build

Pure Node.js, zero third-party dependencies. Licensed under Apache-2.0.

cli/test/fixtures/.gitignore

@@ -0,0 +1,2 @@
+# smoke test fixtures（只读副本，不提交）
+*.prefab