Check bundle formula link status

[MikeMcQuaid]

• Ensure brew bundle check catches formulae with wrong links
• Match implicit link expectations used by brew bundle install
• Cover check, check --verbose and check --install

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[Copilot]

Pull request overview

This PR extends brew bundle check to validate whether installed formulae match the Brewfile’s expected link/unlink state (including implicit expectations), aligning check behavior with what brew bundle install would do and adding spec coverage for the new failure mode.

Changes:

• Add link-status evaluation to formula “installed and up-to-date” checking and provide a specific failure message for link mismatches.
• Refactor link/unlink decision logic into a shared helper used by both checking and install-time link state changes.
• Add bundle check specs covering non-verbose, --verbose, and --install scenarios for link-status mismatches.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
Library/Homebrew/bundle/brew.rb	Adds link-status checking logic and refactors expected link behavior into shared helpers used by both check and install link/unlink operations.
Library/Homebrew/test/cmd/bundle/check_subcommand_spec.rb	Adds test coverage for formula link-status mismatches across check modes (default, --verbose, --install).

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