feat: filter installed skills by agent

[adity982]

Adds case-insensitive --agent/-a filtering to rolecraft list with focused CLI and command tests; closes #119.

[sametcelikbicak]

Thanks for opening this, @adity982! The feature is well-scoped and the implementation looks clean — good work on the case-insensitive filtering, the missing-arg validation, and the Windows USERPROFILE addition.

However, since you opened this PR, the Node.js API refactor (PR #159) was merged into main. This means:

1. Merge conflict — src/commands/list.js has been refactored: it now calls apiList() from src/api/list.js and only handles CLI output. Your filtering logic landed right where the business logic used to live, but in the new structure it belongs in the API layer.

2. What to do on rebase:

   • Rebase on latest main
   • Move the agent filter to src/api/list.js (the apiList function should accept options.agent and filter before returning)
   • In src/commands/list.js, just pass options.agent through to apiList
   • Update tests accordingly (they now test at the API level too)

3. Minor nit: When displaying Installed skills for cursor:, consider showing the original agent flag from the lockfile rather than the lowercased input — it makes the output more predictable.

Would you like any help with the rebase? Happy to review once it's updated.

[adity982]

Thanks for the clear rebase guidance. I will keep this draft until it is rebased on current main, the filter moves into src/api/list.js, the CLI passes options.agent through, and the updated API/CLI tests cover the behavior and display casing.