Update Oklahoma 2025 Individual Income Tax Model

[DTrim99]

Summary

Updates the Oklahoma individual income tax implementation for tax year 2025.

Fixes #7060

Key Changes

• Pension Subtraction Limit (CRITICAL): Update from $10,000 to $20,000 effective 2024 per HB 2020
• 2025 References: Add 2025 form references to all 29 Oklahoma tax parameter files
• Tests: Add 2025 test cases including pension subtraction verification

Parameter Files to Update

Critical Value Change

• pension_limit.yaml - Update to $20,000 for 2024+

Reference Updates (29 files)

• Tax rate files (5 files)
• Deduction files (2 files)
• Exemption files (3 files)
• AGI subtraction files (4 files)
• EITC files (1 file)
• Child/CDCC credit files (3 files)
• Property tax credit files (4 files)
• Sales tax credit files (4 files)
• Credit list files (2 files)
• Misc files (1 file)

Status

• Documentation collected
• Parameters updated
• Tests written
• CI passing

Reference Documents

• 2025 Form 511-NR-Pkt
• 2025 Form 511-Pkt
• 2025 Form 538-H
• 2025 Form 538-S
• 2025 Form 511-EIC

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This is a draft PR. Implementation work is in progress.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.28%. Comparing base (0b01827) to head (45bd0f7).
⚠️ Report is 6 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #7061       +/-   ##
===========================================
+ Coverage   73.03%   99.28%   +26.25%     
===========================================
  Files        3550       16     -3534     
  Lines       51113      280    -50833     
  Branches      263        1      -262     
===========================================
- Hits        37328      278    -37050     
+ Misses      13770        1    -13769     
+ Partials       15        1       -14     

Flag	Coverage Δ
unittests	99.28% <100.00%> (+26.25%)	⬆️

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[DTrim99]

📋 PR Review Summary

✅ Overall Assessment: APPROVE

This is a well-structured PR that updates Oklahoma income tax for 2025. The implementation follows PolicyEngine best practices with proper parameterization and comprehensive documentation.

✅ Strengths

1. Proper Parameter Update: The pension subtraction limit increase from $10,000 to $20,000 (effective 2024) is correctly implemented with proper reference to HB 2020
2. Comprehensive Test Coverage: Good coverage with clear calculation comments in tests
3. Excellent Documentation: Variables include detailed docstrings with calculation examples and legislative history
4. No Hard-coded Values: All values are properly parameterized
5. Correct References: 2025 form references added systematically across all parameter files
6. CI Passing: All tests and lint checks pass

🔍 Minor Observations

1. Implementation Tracking File: The .implementation_ok_2025_tax.md file appears to be a development tracking file. Consider removing it before merge as it may not need to be in the repository long-term.

2. 2025 Form References: The references use 511-NR-Pkt.pdf (nonresident form instructions) for 2025. This is likely because the 2025 resident form (511-Pkt.pdf) may not be published yet. This is acceptable but worth noting for future updates when the resident form becomes available.

📊 Validation Results

• Domain Validation: ✅ No issues - proper state-specific naming and structure
• Reference Validation: ✅ All parameter values have proper references
• Implementation Validation: ✅ No hard-coded values, proper vectorization
• Test Coverage: ✅ Comprehensive tests including edge cases for pension limits and credits

📝 Test Coverage Highlights

The PR includes excellent test cases for:

• Pension subtraction: Tests for both old ($10k) and new ($20k) limits across 2021-2025
• EITC: Part-year resident proration and zero income edge cases
• Sales Tax Credit: Multiple pathways (low income, elderly, disabled, dependents)
• Child Care/Child Tax Credit: CDCC vs CTC comparison, AGI limits, part-year residents
• Integration tests: Complete tax calculation flows for various household scenarios

✅ Recommendation

Ready to merge. This is a quality implementation with proper documentation, comprehensive tests, and correct parameter updates.

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🤖 Generated with Claude Code

[DTrim99]

Well-structured implementation of Oklahoma 2025 tax updates with proper parameterization and comprehensive test coverage. See summary comment for details. This implementation follows PolicyEngine best practices and is ready for merge.