Document SNAP work requirement modeling simplifications and fix mislabeled HR1 parameter

[daphnehanse11]

Fixes #8866

Documentation/metadata-only PR — no behavior changes.

Changes

1. ABAWD 3-in-36 time limit (meets_snap_abawd_work_requirements.py): adds a documentation attribute explaining that 7 CFR 273.24(b) disqualifies an ABAWD only after 3 countable months in 36, with regaining provisions (80 hours in 30 days, 273.24(d)) and one bonus 3-consecutive-month allotment (273.24(e)). The model treats noncompliance as immediate monthly ineligibility — a steady-state assumption that overstates ineligibility for new spells, largest in FY2026 as HR1 restarts time-limit clocks.
2. Voluntary quit / reduced work effort (meets_snap_general_work_requirements.py): adds a documentation attribute noting that 7 CFR 273.7(j) disqualifications are not modeled, since job-separation events are unobservable in cross-sectional survey data.
3. Mislabeled HR1 parameter (gov/usda/snap/work_requirements/abawd/in_effect.yaml): the description and label said it "removes the exemption ... for homeless individuals or veterans," but it gates all HR1 ABAWD changes (higher exempted age threshold, lower dependent-child age threshold, exemption removals and additions). Rewritten accurately; references kept.
4. Annual hours proxy: comments in both work requirement variables where weekly_hours_worked_before_lsr is read over period.this_year, noting the annual-average proxy for what is legally a monthly determination (20 hrs/week averaged monthly / 80 hrs/month per 7 CFR 273.24(a)(1); 30 hrs/week per 273.7(b)(1)(vii)).
5. Annual UC receipt (is_snap_work_registration_exempt_non_age.py): comment noting that annual unemployment compensation receipt exempting all months of the year is a simplification.

The optional parameterized grace-months fraction from the issue is deliberately excluded to keep this PR docs-only; it can follow in a separate PR if wanted.

Testing

policyengine-core test policyengine_us/tests/policy/baseline/gov/usda/snap/eligibility/work_requirements -c policyengine_us — 61 passed, unchanged.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (fa285ae) to head (bbeadff).
⚠️ Report is 640 commits behind head on main.

Additional details and impacted files

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  Coverage   100.00%   100.00%           
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  Files            5         3    -2     
  Lines           62        72   +10     
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+ Hits            62        72   +10     

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

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