- TestsController: Remove duplicate rangeTypeOptions assignment that was being
set inside the NUM condition block, causing it to be set unnecessarily
when it's also handled elsewhere
- ResponseTrait: Convert global helper function convert_empty_strings_to_null()
to private class method convertEmptyStringsToNull() for better encapsulation
and to avoid dependency on global functions
- Database schema: Update clqms_database.dbml with accurate table structure
derived from app/Models/ directory, reorganizing tables by functional
categories (Patient, Visit, Organization, Location, Test, Specimen,
Order, Contact management)
