chore: prepare 0.2.3 release

[dpaluy]

Summary

• Bump reducto_ai from 0.2.2 to 0.2.3.
• Document the merged YARD, Rake, IRB, Minitest, and RuboCop dependency updates.
• Keep the release diff limited to the version and changelog files.

Verification

• Local Ruby 4.0.3: bundle exec rake — 119 runs, 241 assertions, 0 failures, 0 errors, 0 skips; RuboCop inspected 32 files with no offenses.
• bundle exec rake yard — generated documentation for 17 files; 79.38% documented.
• gem build reducto_ai.gemspec --output /tmp/reducto_ai-0.2.3.gem — built reducto_ai 0.2.3 successfully.
• Built-gem metadata/data inspection — no Gemfile.lock entry.
• ruby -c lib/reducto_ai/version.rb — Syntax OK; version check reports 0.2.3.
• git diff --check — clean.

This PR prepares the release only. It must not be merged, tagged, or published by this maintenance job.