When a directory argument is provided to `gh skill publish`, the remote
detection now correctly uses the target directory's git remotes instead
of the current working directory's remotes.
Previously, `detectGitHubRemote` used the factory-provided git client
which pointed to the CWD. This meant that running
`gh skill publish /path/to/repo-bar` from inside repo-foo would detect
repo-foo's remotes and potentially create the release on the wrong repo.
The fix copies the git client and sets `RepoDir` to the target directory,
matching the pattern already used by `detectMissingRepoDiagnostic` and
`checkInstalledSkillDirs`.
Co-authored-by: BagToad <47394200+BagToad@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>