Keep macOS Homebrew setup lazy so users with supported Node and Git can install without admin/Homebrew, while still installing Homebrew before macOS Node or Git package installs.
Updates installer docs and adds focused install.sh coverage for the lazy Git path. Also aligns the live-media provider expectation with current main so built-artifact checks stay green.
Fixes#83232
Co-authored-by: Sebastien Tardif <sebtardif@ncf.ca>
527b7c2eed
