chore: release v0.4.0

[laynepenney]

Release v0.4.0

Highlights

• Griptrees - Work on multiple branches simultaneously with worktree-based parallel workspaces
• Performance - 3.4x speedup on status, 1.8x on branch-check via parallelization
• CI - Automated build/test/benchmarks on Node 18, 20, 22

New Commands

gr griptree add <branch>     # Create parallel workspace
gr griptree list             # Show all griptrees
gr griptree remove <branch>  # Remove a griptree
gr griptree lock <branch>    # Protect from removal
gr griptree unlock <branch>  # Allow removal

Version Changes

• package.json: 0.3.1 → 0.4.0
• src/index.ts: 0.3.1 → 0.4.0
• CHANGELOG.md: [Unreleased] → [0.4.0]

After Merge

1. Create GitHub release: gh release create v0.4.0 --generate-notes
2. Update Homebrew formula with new version and SHA256