Add support for the --allow-hidden-dirs flag in `gh skill preview`,
matching the existing pattern in `gh skill install`. This allows users
to preview skills located in hidden directories (e.g. .claude/skills/,
.agents/skills/).
Changes:
- Add AllowHiddenDirs field to PreviewOptions
- Register --allow-hidden-dirs flag on the preview command
- Switch from DiscoverSkills to DiscoverSkillsWithOptions to get all
skills including hidden-dir ones
- Add filterHiddenDirSkills to exclude hidden-dir skills by default,
showing a hint when they are found but excluded
- Print a warning when --allow-hidden-dirs is used and hidden skills
are present
- Return an error when only hidden-dir skills exist without the flag
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
8498bdf435