Add Minnesota renter's credit

[PavelMakarchuk]

Summary

• add Minnesota renter's credit variables and parameters
• wire the credit into Minnesota refundable credits and the state property tax credit umbrella
• add regression and integration coverage for ordinary renter-credit cases

Testing

• python policyengine_us/tests/test_batched.py policyengine_us/tests/policy/baseline/gov/states/mn/tax/income/credits/mn_rent_constituting_property_taxes.yaml --batches 1
• python policyengine_us/tests/test_batched.py policyengine_us/tests/policy/baseline/gov/states/mn/tax/income/credits/mn_renters_credit_household_income.yaml --batches 1
• python policyengine_us/tests/test_batched.py policyengine_us/tests/policy/baseline/gov/states/mn/tax/income/credits/mn_renters_credit.yaml --batches 1
• python policyengine_us/tests/test_batched.py policyengine_us/tests/policy/baseline/gov/states/mn/tax/income/mn_integration.yaml --batches 1
• python policyengine_us/tests/test_batched.py policyengine_us/tests/policy/baseline/gov/states/mn/tax/income --batches 1
• python -m pytest policyengine_us/tests/policy/baseline/gov/tax/income/test_legacy_state_umbrellas.py -q

Fixes #7938

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (bac2ba3) to head (856105e).
⚠️ Report is 402 commits behind head on main.

Additional details and impacted files

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  Files           19         6    -13     
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- Hits           336        92   -244     

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[DTrim99]

Found one issue to address:

[P2] Prorate assisted rent with AGI, not household income

In policyengine_us/variables/gov/states/mn/tax/income/credits/mn_renters_credit.py around lines 32-37, the assistance-paid-rent fraction is using mn_renters_credit_household_income, which is after age/disability/dependent/SEIU subtractions. Minn. Stat. 290.0693 Subd. 6(b) defines this fraction with adjusted gross income in both numerator and denominator, so older/disabled/dependent claimants in assisted facilities get under-credited here. Please base the proration ratio on the pre-subtraction household AGI/line-5 amount and add a test where assistance rent combines with an age or dependent subtraction.

[DTrim99]

PR Review (via /review-pr)

🔴 Critical (Must Fix)

1. CI failure — Full Suite - Rest is failing with a microsimulation entity mismatch when calling household_net_income:

   ValueError: Input [...] is not a valid value for the entity household
     (size = 41314 != 669 = count)
   

   The failure surfaces inside the adds chain that eventually calls person_weight → person.household(\"household_weight\", period). Unit/YAML tests pass, but the vectorized microsim path does not. Because mn_renters_credit is newly rolled into mn_refundable_credits (and taxsim_state_property_tax_credit via gov.states.household.state_property_tax_credits), the interaction with household_net_income needs to be reproduced locally with Microsimulation(dataset='hf://policyengine/policyengine-us-data/enhanced_cps_2024.h5') and sim.calc('household_net_income', period=2025) to isolate the offending variable. This blocks merge.

2. Broken dependent-claimant exclusion — mn_renters_credit_eligible.py:25-28:

   claimants = tax_unit.members(\"is_tax_unit_head_or_spouse\", period)
   claimant_is_dependent = tax_unit.any(
       claimants & tax_unit.members(\"is_tax_unit_dependent\", period)
   )

   A tax unit head/spouse is never also a tax unit dependent by definition, so claimant_is_dependent is always False and the Minn. Stat. §290.0693 Subd. 1(i) "cannot be claimed as a dependent" disqualification is inoperative. is_tax_unit_dependent describes dependents within this tax unit, not whether the filer is claimed on someone else's return. Needs a different signal (e.g., an explicit input flag or a variable like is_tax_unit_claimed_dependent).

3. Existing reviewer (DTrim99) — assisted-rent proration: Minn. Stat. §290.0693 Subd. 6(b) prorates rent constituting property taxes for rent-assisted residences using the AGI/line-5 amount in both numerator and denominator. The current mn_rent_constituting_property_taxes just multiplies net rent (after housing_assistance) by 17%, which under-credits older/disabled/dependent claimants in assisted facilities. Please resolve that thread explicitly.

🟡 Should Address

1. Duplicate max_credit > 0 check: mn_renters_credit_eligible.py:35 includes (p.max_credit.calc(household_income) > 0), but mn_renters_credit.py:30 already applies min_(max_credit, ...). The eligibility check happens twice.

2. age_threshold.yaml — period field: Age threshold values don't prorate or accumulate — other age-threshold parameters in the codebase use period: eternity. Current file uses period: year.

3. Code-style: unnecessary parameter alias — mn_rent_constituting_property_taxes.py:17 binds p = parameters(period).gov.states.mn.tax.income.credits.renters and only uses p.rent_fraction. Either rename for clarity or access directly.

4. Code-style: nested p.credits.renters.* accessors in mn_renters_credit_household_income.py — p = parameters(period).gov.states.mn.tax.income then p.credits.renters.age_threshold, p.credits.renters.dependent_subtraction_multiplier. Clearer to bind the alias at the .renters level.

5. Variable name claimants (in both mn_renters_credit_eligible.py and mn_renters_credit_household_income.py) refers to head-or-spouse status; claimant in the MN statute has a specific meaning tied to the filer. Consider is_head_or_spouse for clarity.

6. mn_rent_constituting_property_taxes uses p.rent_fraction, but that parameter is scalar with unit: /1 and period: year. The 17% rate is actually statutory and has been stable since 2014; consider period: eternity and cite Minn. Stat. §290.0693 Subd. 1(j) more directly (current ref is correct but the period is misaligned).

7. Test gaps:

   • No test where filer is claimed as dependent elsewhere (exclusion rule) — blocked by critical Run black formatting on docs #2.
   • No test where percent_of_income * household_income > rent_constituting_property_taxes (excess_rent clamps to 0).
   • No test for >5 dependents (above highest bracket).
   • Integration test mn_integration.yaml Case 3 only covers a single filer — add a case with age ≥ 65 or disability subtraction to confirm the household-income chain.

🟢 Suggestions

1. Parameter description style: Descriptions like "Minnesota sets the minimum age for the age-based household income subtraction under the renter's credit" deviate from the standard pattern ([State] [verb] this [X] under the [Full Program Name] program). Consider "Minnesota sets this minimum age for the age-based household income subtraction under the Renter's Credit program" etc.

2. Label consistency: mn_renters_credit_qualifying_crp label \"Has a qualifying Minnesota renter's credit CRP\" is written as a verb phrase; the rest of the PR uses noun phrases.

3. References: The PDF URLs under /2026-03/ are future-dated (MN's 2025 return materials). Worth confirming these URLs are stable in MN's CMS.

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Validation Summary

Check	Result
Regulatory accuracy	2 issues (dependent-claimant check, assisted-rent proration)
Reference quality	Acceptable; minor style
Code patterns	5 style/pattern issues
Test coverage	4 gaps
CI status	1 failing (microsim)

Next Steps

To auto-fix fixable items: /fix-pr 7956. CI failure and statutory issues (critical #2 and #3) likely need human review.