Remove macOS Development Environment Artifacts

Clean up committed .DS_Store files and prevent future commits of development environment artifacts.

Acceptance Criteria:

• Remove all .DS_Store files from repository
• Update .gitignore to exclude macOS artifacts
• Add pre-commit hooks to prevent future artifacts
• Document development environment setup guidelines

Related Files:

• ArtisanPackUIStandard/.DS_Store (remove)
• .gitignore (update)