Git worktree manager

Always use the manager script

Never call git worktree add directly -- always use the worktree-manager.sh script.

The script handles critical setup that raw git commands don't:

1. Copies .env, .env.local, .env.test, etc. from main repo
2. Ensures .worktrees is in .gitignore
3. Creates consistent directory structure
4. After creation, install dependencies if detected: package.json → npm install, composer.json → composer install, pyproject.toml → pip install -e ., go.mod → go mod download

Safety Verification

Before creating a worktree, verify the worktree directory is gitignored:

# Verify .worktrees is ignored (should output ".worktrees")
git check-ignore .worktrees || echo "WARNING: .worktrees not in .gitignore"