Drop Ruby 3.2 from CI test matrix

[ahaverbuch]

Remove Ruby 3.2 from CI test matrix, bump minor version.

Ruby 3.2 EOL prep — aligning CI matrix with supported versions.

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Note

Medium Risk
Raises the minimum supported Ruby to 3.3 and removes Ruby 3.2 from CI, which is a breaking support change for any Ruby 3.2 consumers. Remaining changes are dependency/lockfile updates tied to the new supported matrix.

Overview
Drops Ruby 3.2 from the GitHub Actions test matrix and updates the gemspec to require Ruby >= 3.3.0.

Bumps stator to 0.10.0 and refreshes appraisal lockfiles accordingly, including adding a new activerecord_8.1.gemfile.lock and updating the activerecord_8.0 lock to Rails 8.0.5.

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