Implement Keep Your Pay Act reform with 10-year impacts (2026-2035)

[DTrim99]

Summary

Implement the full Keep Your Pay Act reform calculation logic using PolicyEngine, supporting 10-year budget window impacts from 2026 to 2035.

Reform Components

The reform includes:

• Standard deduction increases: $37,500 single / $75,000 MFJ (with annual inflation adjustments)
• CTC expansion: $3,600 base amount for children (increasing annually)
• EITC changes: Expanded age eligibility (19-200), adjusted phase-in/out rates (15.3%), and updated thresholds
• AFA integration: Uses gov.contrib.congress.afa.in_effect parameter

Technical Tasks

• Update kypa_calc/reforms.py with reform definition
• Implement kypa_calc/household.py household impact calculations
• Implement kypa_calc/microsimulation.py for national impacts
• Update backend API routes for multi-year support
• Update frontend to display 10-year projections
• Add precompute scripts for national impact data

Budget Window

2026-2035 (10 years)