- replace the POSIX shell fixture with a compiled Go helper named hub or hub.exe
- prepend the helper directory to PATH in TestMain so tests cannot invoke an installed hub binary
- add PowerShell build, install, and Windows path examples to the README
- ignore the generated stack-sync.exe binary
- discover nested Git repositories and skip dependency and build directories
- add scan and sync commands with root, exclude, jobs, timeout, JSON, strict, and confirmation options
- block detached heads, missing remotes, active Git operations, and dirty worktrees
- exclude nested repositories from their parent's dirty-worktree check
- recheck repository safety before running hub sync
- add discovery, safety, sync, JSON, and output tests
- set the embedded version to 0.1.1 and document installation and usage