Include Medicare Part A and Part D premiums in MOOP

[daphnehanse11]

Summary

• add a net medicare_part_a_premium variable for Part A premiums paid out of pocket
• add msp_part_a_premium_coverage so QMB-covered Part A premiums do not count as household MOOP
• include paid Part A premiums and Part D IRMAA in SPM health insurance premiums and medical out-of-pocket expenses

Fixes #8529.

Tests

uv run python -m policyengine_core.scripts.policyengine_command test -c policyengine_us policyengine_us/tests/policy/baseline/gov/hhs/medicare/eligibility/medicare_part_a_premium.yaml policyengine_us/tests/policy/baseline/gov/hhs/medicare/savings_programs/msp_part_a_premium_coverage.yaml policyengine_us/tests/policy/baseline/household/income/spm_unit/spm_unit_medical_out_of_pocket_expenses_medicare_part_b.yaml

uv run python -m policyengine_core.scripts.policyengine_command test -c policyengine_us policyengine_us/tests/policy/baseline/gov/hhs/medicare policyengine_us/tests/policy/baseline/household/income/spm_unit/spm_unit_medical_out_of_pocket_expenses_medicare_part_b.yaml

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (ee131a9) to head (e3fb9eb).
⚠️ Report is 95 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##              main     #8532    +/-   ##
==========================================
  Coverage   100.00%   100.00%            
==========================================
  Files            9         4     -5     
  Lines          149        49   -100     
  Branches         0         1     +1     
==========================================
- Hits           149        49   -100     

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

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