rowboat 0.2.1 (new cask)

[SSakutaro]

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After making any changes to a cask, existing or new, verify:

• The submission is for a stable version or documented exception.
• brew audit --cask --online <cask> is error-free.
• brew style --fix <cask> reports no offenses.

Additionally, if adding a new cask:

• Named the cask according to the token reference.
• Checked the cask was not already refused (add your cask's name to the end of the search field).
• brew audit --cask --new <cask> worked successfully.
• HOMEBREW_NO_INSTALL_FROM_API=1 brew install --cask <cask> worked successfully.
• brew uninstall --cask <cask> worked successfully.

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• AI was used to generate or assist with generating this PR. Please specify below how you used AI to help you, and what steps you have taken to manually verify the changes, including zap stanza paths.

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[Copilot]

Pull request overview

Adds a new Homebrew cask for Rowboat v0.2.1.

Changes:

• Introduces rowboat cask with OS/arch-specific download URL and SHA256s.
• Declares a macOS minimum version and adds a zap stanza.

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[krehel]

This was not tested on Linux and style checks were not run.

Please do not check boxes in the PR template that were not performed.

[bevanjkay]

Please also run brew style --fix rowboat after applying the changes in the code review.
Thanks!