- Extract setup_query_extensions and related methods to new QueryExtensions module
- Reduce main aux_table.rb file from 537 to 335 lines (202 lines removed)
- Create lib/active_record/aux_table/query_extensions.rb with RelationMethods
- Fix infinite recursion bug by using super() calls and disabling aux processing on joined relations
- All 47 tests pass and no Sorbet type errors
- Improve code organization and maintainability
- Complete task-19 with all acceptance criteria met
Closes: task-19