Load local skills for a project

[DouglasdeMoura]

Other coding assistants can load skills available for the current project only. What do you think on adding support for that on Crush at .crush/skills and .agents/skills? Also, this is expected by add-skill, as you can see here: https://github.com/vercel-labs/add-skill/blob/main/src/agents.ts.

[hongquan]

Prepared a PR for this feature: #2462
The PR is draft because this new feature is not approved yet.