chore: enforce RubyGems cooldown

[dustinbyrne]

💡 Motivation and Context

Bundler 4.0.13 introduced RubyGems cooldown, which avoids resolving to newly-published gem versions until they have aged past a configured window. This adds a 7-day cooldown to the public RubyGems source so dependency updates are less exposed to compromised-account / malicious-new-release supply-chain windows.

💚 How did you test it?

• bundle _4.0.13_ install
• bundle _4.0.13_ exec rspec
• bundle _4.0.13_ exec rubocop
• Confirmed bundle _4.0.8_ install is blocked with the Gemfile Bundler-version guard instead of silently ignoring cooldown.

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• I updated the docs if needed.
• No breaking change or entry added to the changelog.

If releasing new changes

• Ran pnpm changeset to generate a changeset file

[greptile-apps]

_{Reviews (1): Last reviewed commit: "chore: enforce RubyGems cooldown" | Re-trigger Greptile}