When bd init installs hooks with chaining, it renames the user's original
hook to .old and creates a new bd hook that chains to it. If bd doctor
later runs bd hooks install --chain, it would:
1. Not recognize the inline bd hook (from bd init) as a bd hook
2. Rename it to .old, overwriting the user's original hook
3. Install a new shim hook
This fix addresses two root causes:
1. Detection mismatch: areBdShimsInstalled() and getHookVersion() now
recognize inline bd hooks (which have "# bd (beads)" marker) in
addition to shim hooks (which have "# bd-shim" marker)
2. No .old protection: bd hooks install --chain now checks if .old
already exists before renaming, preserving the user's original hook
Fixes#1120
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
a5140075f1