ZIR-000: Add versioned commit-message hooks with branch-based ticket extraction

[zeroecco]

Summary

• Moves prepare-commit-msg and commit-msg into a tracked hooks/ directory so they are version-controlled alongside the codebase
• Enhances prepare-commit-msg to extract the ZIR ticket number from the current branch name (e.g. ZIR-123-my-feature → ZIR-123:) before falling back to ZIR-000
• Adds commit-msg with an improved error message hinting developers to name branches with a ZIR-XXX prefix
• Adds hooks/install.sh to symlink hooks into .git/hooks/ and make them executable

Test plan

• Run bash hooks/install.sh from the repo root and verify symlinks appear in .git/hooks/
• On a branch named ZIR-42-test-branch, make a commit without a ZIR prefix and verify the message is auto-prefixed with ZIR-42:
• On a branch without a ZIR prefix, verify the fallback ZIR-000: is used
• Verify merge commits are skipped by prepare-commit-msg
• Verify commit-msg rejects a message that does not match ZIR-XXX: ... and displays the branch-naming hint

Nightshift-Task: commit-normalize
Nightshift-Ref: https://github.com/marcus/nightshift

🤖 Generated with Claude Code