Fix AZ property tax credit table selection for married couples

[PavelMakarchuk]

Summary

az_property_tax_credit (Form 140PTC) selected the Table 1 (living-alone) schedule for married couples, roughly quartering the credit. It relied on cohabitating_spouses, a no-formula input defaulting to False, so a married-filing-jointly couple living together was treated as not cohabitating.

Per ARS §43-1072(A)(3), a claimant who "lived with a spouse or one or more persons" uses the Table 2 schedule (§43-1072(B)(2)); only a claimant who "did not live with a spouse or any other persons" uses Table 1. A married couple living together falls under Table 2.

Fix

Treat the tax unit as cohabitating when it is married (tax_unit_married), in addition to the existing cohabitating_spouses flag. This is a local fix in az_property_tax_credit rather than changing the global cohabitating_spouses default, which also feeds Social Security taxability, Medicaid household size/income, and the NJ property tax credit.

Impact

AZ MFJ, both age 75, $3,638 household income, $9,059 rent, TY2025:

	Table	az_property_tax_credit
Before	Table 1 (living alone)	$78
After	Table 2 (cohabitating)	$323

$323 matches the ARS §43-1072(B)(2) table (household income $3,551–3,700 → $323), PE's own Table 2 parameter, and the reporter's filled 2025 Form 140PTC.

Tests

Added the issue's integration test to az_property_tax_credit.yaml. Full AZ baseline sweep: 468 passed.

Originating TAXSIM comparison: PolicyEngine/policyengine-taxsim#983

Fixes #8649

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (f9e58e7) to head (047f3c3).
⚠️ Report is 46 commits behind head on main.

Additional details and impacted files

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  Coverage   100.00%   100.00%           
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  Files            3         1    -2     
  Lines           55        16   -39     
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- Hits            55        16   -39     

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

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