Summary

Closes #610

Adds detection for hk as an external hook manager, following the same filesystem-based detection pattern used for Husky, Lefthook, and other existing hook managers.

hk uses .pkl config files with four possible locations:

• hk.pkl (root)
• hk.local.pkl (root, local override)
• .config/hk.pkl (config dir)
• .config/hk.local.pkl (config dir, local override)

All four variants are checked, and results are deduplicated so hk only appears once in the detected list regardless of how many config files exist.

Changes

• hook_managers.go - Added hk detection block generating checks for all 4 config file variants
• hook_managers_test.go - Added 4 tests: basic detection, .config/ dir variant, .local variant, and deduplication across multiple config files

Testing

• All 4 new tests pass
• Follows existing test patterns (isolated temp repos with testutil.InitRepo, t.Parallel())
• Verified deduplication works when multiple hk config files exist simultaneously

Generated with Claude Code

Co-Authored-By: Claude Opus 4.6 noreply@anthropic.com