test: Add test coverage for BMI categorization in case service

[iamkaroko]

SUMMARY

Problem

This PR addresses two main needs:

1. Data Export Capability: The research team needed a way to export answer data collected from participants in CSV format for analysis and reporting purposes.
2. BMI Display Enhancement: Case details were showing raw BMI numeric values instead of human-readable categories (Underweight, Normal, Overweight, Obese).

Solution

Answer Export Scripts

• Created two export scripts (export_answers_to_csv.py and export_answers_to_csv_new_format.py) to extract answer data from the database and format it for analysis
• Added comprehensive README documentation for the export functionality
• Included sample exported data for reference

BMI Categorization

• Modified case_service.py to detect BMI measurements (concept_id 40490382) and convert numeric values to categories:
  • 18 → Underweight
  • 22 → Normal
  • 27 → Overweight
  • 30 → Obese
  • Other values → Display numeric value as string

Round 3 Configuration

• Added utilities for Round 3 test configuration management
• Created generate_round3_test_config.sh script
• Added remove_all_case_assignments.py utility
• Included round3_test_config.csv with test data

Cleanup

• Removed outdated config.csv file (25K+ lines)
• Updated dependencies in Pipfile

TEST PLAN

Manual Testing

1. BMI Display

   • Navigate to a case with BMI measurements
   • Verify BMI values display as categories instead of numbers
   • Confirm other measurements still display correctly

2. Answer Export

   • Run python script/answer_export/export_answers_to_csv.py
   • Verify CSV file is generated with correct format
   • Check that all answer data is properly formatted

3. Round 3 Configuration

   • Run ./script/assign_cases/generate_round3_test_config.sh
   • Verify configuration file is generated
   • Test case assignment removal script

Automated Testing

• Added 5 new unit tests for BMI categorization covering:
  • ✅ Underweight category (BMI 18)
  • ✅ Normal category (BMI 22)
  • ✅ Overweight category (BMI 27)
  • ✅ Obese category (BMI 30)
  • ✅ Unknown/other BMI values (fallback to numeric string)
• All 175 tests passing (170 existing + 5 new)
• Test coverage maintained at 96.42% (above 96.4% threshold)

CI/CD

• ✅ All tests pass
• ✅ Code coverage meets requirements
• ✅ Linting checks pass
• ✅ Security scans complete

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Pre-merge author checklist

• I've clearly explained:
  • What problem this PR is solving.
  • How this problem was solved.
  • How reviewers can test my changes.
• I've included tests I've run to ensure my changes work.
• I've added unit tests for any new code, if applicable.
• I've documented any added code.