Move bottle CI workflow helpers into brew

[p-linnane]

This adds brew generate-bottle-ci-matrix, which builds the dispatch-build-bottle runner matrix and rejects runners whose bottle already exists, and brew update-portable-ruby --print-target-version, which prints the revision-aware pkg_version without writing anything. Both replace github-script and brew ruby steps in homebrew-core so the logic is typed and tested here.

The matrix matches the removed JavaScript. The bottle check fixes two gaps in the inline Ruby: linux-arm64 was checked as x86_64_linux, and minor macOS versions such as 15.4-arm64 were never checked. Existing bottles surface as error annotations via ofail with a non-zero exit. The homebrew-core side is Homebrew/homebrew-core#302687 and lands after this.

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• Have you followed our Contributing guidelines?
• Have you checked for other open Pull Requests for the same change?
• Have you explained what your changes do? Performance claims (e.g. "this is faster") must include brew benchmark results.
• Have you explained why you'd like these changes included, not just what they do?
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• Have you written new tests (excluding integration tests)? Here's an example.
• Have you successfully run brew lgtm (style, typechecking and tests) locally?

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• I did not use AI/LLM to create this PR, or I disclosed the tool/model below and reviewed its output; I did not attribute commits to AI and will answer maintainer questions and review comments myself without AI/LLM.

Claude Code (Fable 5.1) drafted the implementation and tests; I reviewed the diff, verified the new tests fail without the change and pass with it, and ran brew lgtm --online plus targeted specs.

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[MikeMcQuaid]

Thanks!

[Copilot]

🟡 Changes recommended

The new single-use helper methods violate the repository’s explicit inlining convention.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

Adds typed, tested brew commands to replace inline workflow scripting in homebrew-core.

Changes:

• Generates bottle CI runner matrices and detects existing bottles.
• Adds a read-only portable Ruby target-version option.
• Updates tests, RBI files and generated completions.

File summaries

File	Description
Library/Homebrew/dev-cmd/generate-bottle-ci-matrix.rb	Implements matrix generation and bottle checks.
Library/Homebrew/dev-cmd/update-portable-ruby.rb	Adds target-version output mode.
Library/Homebrew/test/dev-cmd/generate-bottle-ci-matrix_spec.rb	Tests runner mapping and failures.
Library/Homebrew/test/dev-cmd/update-portable-ruby_spec.rb	Tests version output.
Library/Homebrew/sorbet/rbi/dsl/homebrew/dev_cmd/generate_bottle_ci_matrix.rbi	Adds generated argument types.
Library/Homebrew/sorbet/rbi/dsl/homebrew/dev_cmd/update_portable_ruby.rbi	Types the new switch.
completions/bash/brew	Adds Bash completions.
completions/fish/brew.fish	Adds fish completions.
completions/zsh/_brew	Adds zsh completions.

Review details

Files not reviewed (2)

• Library/Homebrew/sorbet/rbi/dsl/homebrew/dev_cmd/generate_bottle_ci_matrix.rbi: File type not supported
• Library/Homebrew/sorbet/rbi/dsl/homebrew/dev_cmd/update_portable_ruby.rbi: File type not supported

Suppressed comments (1)

Library/Homebrew/dev-cmd/generate-bottle-ci-matrix.rb:77

• This helper is likewise called only once and is not needed for direct unit testing. To comply with AGENTS.md:5, inline the matrix-entry construction into the runners.map block.

      def runner_spec(runner, github_run_id)

• Files reviewed: 7/9 changed files
• Comments generated: 1
• Review effort level: Balanced

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