Backdate Colorado SSP parameters

[mattunrath]

Summary

Backdates Colorado AND-CS (Aid to the Needy Disabled - Colorado Supplement) parameters to 2002 and expands test coverage.
Closes #7795

Changes

• Parameters backdated: 2 files, 18 new date entries added to grant_standard.yaml (2002-2022)
• age_range.yaml: Backdated from 2023 to 2002 (same eligibility: ages 0-59, blind or disabled)
• Tests expanded: From 8 to 19 test cases covering historical periods (2002, 2005, 2009, 2012, 2014), boundary conditions, and edge cases
• References updated: Added SSA State Assistance Report citations and Colorado CCR 9 CCR 2503-5 section references

Program Details

Colorado's AND-CS grant standard equals the combined SSI + state supplement amount for the "living independently" category:

• 2002-2004: FBR + $37 SSP (e.g., $545 + $37 = $582 in 2002)
• 2005-2011: FBR + $25 SSP (e.g., $674 + $25 = $699 in 2009)
• 2012+: Grant standard = FBR only (state supplement eliminated for this category)

Regulatory Sources

• SSA State Assistance Programs for SSI Recipients, Jan 2002 - Colorado
• SSA State Assistance Programs for SSI Recipients, Jan 2011 - Colorado
• 9 CCR 2503-5, Section 3.546, AND-CS Program (2014)
• 9 CCR 2503-5, Section 3.546, AND-CS Program (2023)

Needs Human Decision

• 2003 grant standard ($589) is interpolated — no SSA report found for that year. FBR was $552, SSP likely $37 (same as 2002/2004).
• 2012-2013 transition: unclear exactly when Colorado dropped the $25 SSP. Currently using FBR-only ($698/$710).
• Couple amounts not modeled — current implementation is individual-only. SSA reports show couple SSP was $339-$387 (2002-2011).

Test Plan

• All 12 co_state_supplement tests pass (verified via Simulation API)
• 7 co_state_supplement_eligible tests properly formatted
• CI pipeline validation

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.93%. Comparing base (a357860) to head (b5bdb05).
⚠️ Report is 15 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7796      +/-   ##
==========================================
+ Coverage   73.68%   73.93%   +0.24%     
==========================================
  Files        3909     3909              
  Lines       56401    56401              
  Branches      270      270              
==========================================
+ Hits        41560    41698     +138     
+ Misses      14821    14678     -143     
- Partials       20       25       +5     

Flag	Coverage Δ
unittests	73.93% <ø> (+0.24%)	⬆️

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