Workaround can be removed: isHidden bug fixed

[github-actions]

The upstream issue anthropics/claude-code#17271 has been closed.

Action Required

Remove the workaround from .claude-plugin/plugin.json:

1. Remove the commands array that lists skill directories
2. Test that skills now appear in / autocomplete with /bmad: prefix
3. Update docs/workarounds.md

See docs/workarounds.md for full removal steps.