Keep parsed and evaled stdout free of warnings #24015

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  brew bundle env --check, exec --check and sh --check run the checker without redirecting stdout, so Skipping lines for entries in HOMEBREW_BUNDLE_*_SKIP or unsupported on the platform corrupted eval "$(brew bundle env --check)" and piped brew bundle check. Print them with opoo like other warnings, without a GitHub Actions annotation as they are routine, and let the OS prepends supply only the reason so the warning is printed in one place. Drop the unused silent: keyword.


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  brew update --auto-update runs before brew outdated --json and brew bundle env, so its custom Git remote and stashed changes hints now go to stderr like the rest of the update report.


• Loading a cask from a URL printed ==> Downloading into brew info --json=v2 <url>, so guard it on a TTY like api.rb.


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  brew verify --json printed has a valid attestation before the JSON.

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Claude with Fable 5.1 at Extra High effort, with local review and testing.