Detection patterns exist for Rails 6.0+ upgrades but are missing for older upgrade paths.

The version-guides/upgrade-5.1-to-5.2.md guide exists but there is no corresponding detection-scripts/patterns/rails-52-patterns.yml file.

Acceptance criteria

• Create rails-52-patterns.yml covering all breaking changes from the version guide
• Organize patterns into high_priority and medium_priority sections
• Include dependencies section for any bridge/compatibility gems
• Verify YAML parses without errors
• Verify naming convention matches rails-{VERSION}-patterns.yml for auto-discovery by direct-detection-workflow.md