Implements support for installing git hooks to a versioned directory
(.beads-hooks/) that can be committed to the repository and shared with
team members. This solves the team collaboration issue where hooks need
to be installed in pre-built containers.
Changes:
- Add --shared flag to 'bd hooks install' command
- Install hooks to .beads-hooks/ when --shared is used
- Automatically configure git config core.hooksPath
- Update help text to explain shared mode
Fixes#229
