refactor(hook): improve hook path resolution and add worktree/bare repo support

[vivindeena]

Summary

• Convert isCalledFromGitHook to a function for better encapsulation
• Use git rev-parse commands to dynamically resolve hooks directory
• Add support for Git worktrees and bare repositories
• Add comprehensive test coverage for various Git repository configurations

Changes

• Add getGitHooksPath() function using git rev-parse --git-path hooks
• Add getGitDir() helper function for Git directory resolution
• Improve hook install/uninstall to handle absolute and relative hook paths
• Add tests for worktree, bare repo, and subdirectory scenarios

[vivindeena]

somewhat new to testing frameworks, hopefully it makes sense,

PS. also removed the requirement to have OPENAI_API_KEY to test hook integration