Populate education credit inputs

[MaxGhenis]

Summary

• convert the PUF-imputed tax-unit AOTC signal into lower-level Enhanced CPS AOTC eligibility inputs from PolicyEngine US, rather than setting the composite eligibility variable when the new PE-US inputs are available
• populate AOTC data assumptions for unavailable facts such as credential pursuit, eligible institution attendance, 1098-T/exception, institution EIN, no first-four-years completion, and no felony drug conviction for tax units with positive imputed AOTC
• adjust or fill qualified tuition expenses for selected AOTC students by inverting the AOTC amount scale from policyengine-us parameters instead of hardcoding statutory dollar amounts or rates
• populate factual Lifetime Learning Credit inputs in PUF and Extended CPS for non-AOTC tuition records, while leaving legal/effective-date rules in PE-US
• add IRS SOI Table 3.3 refundable AOTC and combined nonrefundable education-credit calibration targets to the Enhanced CPS legacy loss matrix
• use PUF E87530 for LLC-specific expenses where present and keep the release/fallback path compatible with current PE-US builds

Primary Sources

• The PE-US predicates added in Add education credit eligibility inputs policyengine-us#8170 implement 26 U.S.C. § 25A, including § 25A(c), § 25A(f), § 25A(g)(1), § 25A(g)(7), and § 25A(g)(8).
• The AOTC and education-credit calibration targets come from IRS SOI Table 3.3, all returns row, published in Individual Income Tax Returns Complete Report Publication 1304, Basic Tables Part 3.
• Table 3.3 reports LLC only inside the combined nonrefundable education credit, so this PR adds a combined education_tax_credits target, not a standalone LLC calibration target.

Local Build Result

Built EnhancedCPS_2024 locally against PolicyEngine/policyengine-us#8170. Latest aggregate from the calibrated dataset:

• Lifetime Learning Credit potential: $1.278B
• Lifetime Learning Credit: $1.034B over 1.712M weighted positive tax units
• nonrefundable AOTC: $6.779B
• refundable AOTC: $5.166B over 5.615M weighted positive tax units
• full AOTC: $12.915B
• combined nonrefundable education credits: $7.813B over 7.161M weighted positive tax units

The local calibration log reports:

• refundable AOTC target: $5.090B, estimate $5.071B, relative error -0.38%; count target 5.822M, estimate 5.544M, relative error -4.76%
• combined education-credit target: $7.555B, estimate $7.698B, relative error +1.90%; count target 7.211M, estimate 7.066M, relative error -2.02%

Dependency

• Depends on Add education credit eligibility inputs policyengine-us#8170 for the new education-credit eligibility input variables.
• Retains legacy fallbacks so current released PE-US builds do not silently drop the imputed tax-unit AOTC signal before the PE-US release is available.

Tests

• uv run --no-sync ruff check policyengine_us_data/datasets/puf/puf.py policyengine_us_data/datasets/puf/uprate_puf.py tests/unit/datasets/test_puf_tuition.py tests/unit/datasets/test_uprate_puf.py
• uv run --no-sync pytest tests/unit/datasets/test_puf_tuition.py tests/unit/datasets/test_uprate_puf.py -q
• uv run --no-sync pytest tests/unit/calibration/test_loss_targets.py tests/unit/test_etl_irs_soi_overlay.py tests/unit/test_refresh_soi_table_targets.py tests/unit/test_extended_cps.py tests/unit/datasets/test_puf_tuition.py tests/unit/datasets/test_uprate_puf.py -q

Fixes #841

[MaxGhenis]

Local paired build result using this us-data branch with PolicyEngine/policyengine-us#8170:

• Rebuilt PUF, Extended CPS half, and calibrated EnhancedCPS_2024 locally.
• Lifetime Learning Credit: $1.034B over 1.712M weighted positive tax units.
• Nonrefundable AOTC: $6.779B.
• Refundable AOTC: $5.166B over 5.615M weighted positive tax units.
• Full AOTC: $12.915B.
• Combined nonrefundable education credits: $7.813B over 7.161M weighted positive tax units.

Calibration log from the local build:

• Refundable AOTC target: $5.090B, estimate $5.071B, relative error -0.38%; count target 5.822M, estimate 5.544M, relative error -4.76%.
• Combined education-credit target: $7.555B, estimate $7.698B, relative error +1.90%; count target 7.211M, estimate 7.066M, relative error -2.02%.

There is no standalone LLC calibration target in this PR because IRS SOI Table 3.3 reports LLC only inside the combined nonrefundable education credit.