Backdate North Carolina TANF

[hua7450]

Summary

Fixes #7225

Backdates North Carolina TANF parameters from 2024 to 1997 and reorganizes the parameter folder structure.

Justification for Backdating

North Carolina's Work First (TANF) benefit amounts have remained unchanged since 1996:

"North Carolina's Work First program benefit has stayed the same since 1996" — NC Budget & Tax Center

This is also confirmed by NCCP's TANF Profile, which notes NC ranks 48th in benefit amounts nationally.

Changes

Parameters Backdated to 1997-01-01

• payment_percentage: 50%
• age_limit: 18 years
• average_reduced_need_standard_threshold: $25
• earned income sources
• unearned income sources
• additional_person: $50
• need_standard/main table (sizes 1-14)

Folder Reorganization

File	Old Location	New Location
payment_percentage.yaml	need_standard/	benefit/
age_limit.yaml	need_standard/	eligibility/
average_reduced_need_standard_threshold.yaml	need_standard/	eligibility/

New Parameter

• need_standard/max_table_size.yaml (value: 14)

Code Changes

• Updated variable files to reference new parameter paths
• Simplified nc_tanf_need_standard.py using clip() instead of manual min/max logic
• Minor code style cleanup

Test Plan

• Added tests for 2017 and 2018 periods to verify backdating
• Existing tests pass

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (d08239b) to head (767ec5f).
⚠️ Report is 19 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #7227   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            1         5    +4     
  Lines           10        69   +59     
=========================================
+ Hits            10        69   +59     

Flag	Coverage Δ
unittests	100.00% <100.00%> (ø)

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