A.2 Install Homebrew

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

# Apple Silicon — add to PATH
echo 'eval "$(/opt/homebrew/bin/brew shellenv)"' >> ~/.zshrc
source ~/.zshrc

IMPORTANT

Intel Macs: Homebrew at /usr/local/bin (usually on PATH). Apple Silicon: /opt/homebrew/bin — confirm with: brew --version