Add async versions of skill loading functions with concurrency control: - mapWithConcurrency: Generic concurrent mapper with limit (16) - loadSkillFromPathAsync: Async skill file parsing - loadMcpJsonFromDirAsync: Async mcp.json loading - discoverSkillsInDirAsync: Async directory scanner Tests: 20 new tests covering all async functions 🤖 GENERATED WITH ASSISTANCE OF [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)