[codex] Add Medicaid medically frail CE exclusion

[daphnehanse11]

Summary

Closes #8573.

This adds a distinct Medicaid community engagement input for people who are medically frail or have special medical needs, then treats that input as satisfying the federal Medicaid community engagement eligibility check.

The input is intentionally direct rather than derived: the June 1, 2026 CMS IFC ties the full medically frail/special medical needs definition to state condition lists and case review, which is broader than existing disability variables.

Changes

• Add is_medically_frail_or_has_special_medical_needs_for_medicaid_ce.
• Include that input in medicaid_work_requirement_eligible.
• Add YAML cases proving a medically frail adult passes even when is_disabled is false, while the same adult fails without the exclusion.

Validation

• /Users/daphnehansell/Documents/GitHub/policyengine-us/.venv/bin/ruff format policyengine_us/variables/gov/hhs/medicaid/eligibility/is_medically_frail_or_has_special_medical_needs_for_medicaid_ce.py policyengine_us/variables/gov/hhs/medicaid/eligibility/medicaid_work_requirement_eligible.py
• /Users/daphnehansell/Documents/GitHub/policyengine-us/.venv/bin/ruff check policyengine_us/variables/gov/hhs/medicaid/eligibility/is_medically_frail_or_has_special_medical_needs_for_medicaid_ce.py policyengine_us/variables/gov/hhs/medicaid/eligibility/medicaid_work_requirement_eligible.py
• uv run python -m policyengine_core.scripts.policyengine_command test policyengine_us/tests/policy/baseline/gov/hhs/medicaid/eligibility/medicaid_work_requirement_eligible.yaml -c policyengine_us

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (17cda0d) to head (0fc72e1).
⚠️ Report is 9 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #8578   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files            1         2    +1     
  Lines           19        50   +31     
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+ Hits            19        50   +31     

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

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