Add :clear to report transaction tag values (STF-190)

[oschwald]

Summary

• Commit 1 — Adds :clear to the enum_accessor :tag array on
  Minfraud::Components::Report::Transaction, updates the docstring
  (with a parenthetical clarifying that :clear retracts a previous
  report), and extends the valid-values iteration in the component spec.
  Appends a bullet to the existing unreleased v2.10.0 entry in
  CHANGELOG.md.
• Commit 2 — Adds a mise.toml (and generated mise.lock) so
  contributors can mise install to get a working Ruby toolchain. Uses
  ruby = "latest" to match the "latest" convention used in
  minfraud-api-dotnet / GeoIP2-dotnet. Not STF-190 specific —
  separate commit for easy review.

The clear tag retracts a previously reported fraud report on a transaction
(restoring its label to "unknown", distinct from the positive :not_fraud
signal). Backend support shipped in STF-15; this adds SDK support per STF-190.

Linear: https://linear.app/maxmind/issue/STF-190

Test plan

• bundle exec rake (sandbox could not build Ruby from source due
  to missing libssl-dev — relying on CI to verify)
• Change is mechanical: one symbol added to the enum array; spec
  iterates the same array.

🤖 Generated with Claude Code

[gemini-code-assist]

Code Review

This pull request adds the :clear tag to the Minfraud::Components::Report::Transaction component, updating the documentation, the enum_accessor, and the test suite. A suggestion was made to clarify the purpose of the :clear tag in the documentation, specifically noting its use for retracting previous reports.

[gemini-code-assist]

The :clear tag has a specific functional behavior (retracting a previous report) that distinguishes it from the other likelihood-based tags. Adding a brief explanation in the docstring would help users understand its purpose without needing to refer to the external API documentation.

        # This may be one of +:chargeback+, +:clear+ (to retract a previous
        # report), +:not_fraud+, +:spam_or_abuse+, or +:suspected_fraud+.