docs: add contributor guide and validation wrappers - #2279

The following taps are not trusted: aws/tap Homebrew is currently ignoring formulae, casks and commands from these taps because tap trust is required. Untap them with: brew untap aws/tap Trust specific formulae, casks and commands with: brew trust --formula <user>/<tap>/<formula> brew trust --cask <user>/<tap>/<cask> brew trust --command <user>/<tap>/<command> Whole-tap trust is broader and includes all current and future formulae, casks and commands from the listed taps. Trust whole taps with: brew trust aws/tap To disable trust checks: export HOMEBREW_NO_REQUIRE_TAP_TRUST=1 This is not recommended and will be removed in a later release. For more information, see: https://docs.brew.sh/Tap-Trust

`$HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK` is set: not checking for outdated dependents or dependents with broken linkage!

The following taps are not trusted: aws/tap Homebrew is currently ignoring formulae, casks and commands from these taps because tap trust is required. Untap them with: brew untap aws/tap Trust specific formulae, casks and commands with: brew trust --formula <user>/<tap>/<formula> brew trust --cask <user>/<tap>/<cask> brew trust --command <user>/<tap>/<command> Whole-tap trust is broader and includes all current and future formulae, casks and commands from the listed taps. Trust whole taps with: brew trust aws/tap To disable trust checks: export HOMEBREW_NO_REQUIRE_TAP_TRUST=1 This is not recommended and will be removed in a later release. For more information, see: https://docs.brew.sh/Tap-Trust

libffi is keg-only and must be linked with `--force`.

`$HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK` is set: not checking for outdated dependents or dependents with broken linkage!

The following taps are not trusted: aws/tap Homebrew is currently ignoring formulae, casks and commands from these taps because tap trust is required. Untap them with: brew untap aws/tap Trust specific formulae, casks and commands with: brew trust --formula <user>/<tap>/<formula> brew trust --cask <user>/<tap>/<cask> brew trust --command <user>/<tap>/<command> Whole-tap trust is broader and includes all current and future formulae, casks and commands from the listed taps. Trust whole taps with: brew trust aws/tap To disable trust checks: export HOMEBREW_NO_REQUIRE_TAP_TRUST=1 This is not recommended and will be removed in a later release. For more information, see: https://docs.brew.sh/Tap-Trust

Already linked: /opt/homebrew/Cellar/lld@19/19.1.7

llvm@19 was installed but not linked because llvm@20 is already installed. To link this version, run: brew link llvm@19

`$HOMEBREW_NO_INSTALLED_DEPENDENTS_CHECK` is set: not checking for outdated dependents or dependents with broken linkage!