Fix DC CDCC rate to 24.25% for TY2026+ (currently 32%)

[MaxGhenis]

Summary

Fixes #7677.

DC Code § 47-1806.04(c)(1)(B), as amended by the Fiscal Year 2025 Budget Support Act of 2024 (D.C. Act 25-506, sec. 7032, signed July 15, 2024), requires the DC CDCC match rate to drop from 32% to 24.25% for tax years beginning after December 31, 2025.

The statute states:

"(B) For each full calendar or fiscal year beginning after December 31, 2025, there is allowed a credit against the tax imposed by § 47-1806.03 in an amount equal to 24.25% of the amount of the credit to which the resident may be entitled under section 21 of the Internal Revenue Code of 1986"

Changes

• Added 2026-01-01: 0.2425 entry to match.yaml
• Added statute reference to the parameter metadata
• Added two new test cases: TY2025 (still 32%) and TY2026 (24.25%)

Test plan

• Existing TY2021 and TY2022 tests continue to pass at 32%
• New TY2025 test confirms 32% rate still applies
• New TY2026 test confirms 24.25% rate applies

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.45%. Comparing base (5328a32) to head (7754ac9).
⚠️ Report is 400 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##              main    #7683       +/-   ##
============================================
- Coverage   100.00%   73.45%   -26.55%     
============================================
  Files            1     3904     +3903     
  Lines           25    56341    +56316     
  Branches         0      271      +271     
============================================
+ Hits            25    41387    +41362     
- Misses           0    14932    +14932     
- Partials         0       22       +22     

Flag	Coverage Δ
unittests	73.45% <ø> (-26.55%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[DTrim99]

PR Review: Fix DC CDCC Rate to 24.25% for TY2026+

🟢 No Critical Issues Found

This PR is well-implemented and ready to merge.

---

Validation Summary

Check	Result
Regulatory Accuracy	✅ 24.25% matches DC Code 47-1806.04(c)(1)(B)
Reference Quality	✅ Statute explicitly states "24.25%" for years after Dec 31, 2025
Code Patterns	✅ Simple parameter update, no hard-coded values
Test Coverage	✅ Boundary years (2025 at 32%, 2026 at 24.25%) tested
CI Status	✅ All core checks passing

---

What Was Verified

Regulatory Research:

• DC Code 47-1806.04(c)(1)(B) confirms: "If a return is filed for a full calendar or fiscal year beginning after December 31, 2025... an amount equal to 24.25% of the credit allowed under section 21..."
• New rate: 24.25% ✅
• Effective date: Tax years beginning after Dec 31, 2025 (= 2026-01-01) ✅
• FY2025 Budget Support Act (D.C. Act 25-506, sec. 7032) enacted ✅

Test Coverage:

• TY2025: $1,000 × 32% = $320 ✅
• TY2026: $1,000 × 24.25% = $242.50 ✅

---

🟡 Pre-existing Issues (Not Introduced by This PR)

1. Variable reference tuple missing comma:

# In dc_cdcc.py (existing code, not modified by this PR)
reference = (
    "url1"
    "url2"  # Missing comma - causes string concatenation
)

This is not blocking for this PR but could be fixed in a follow-up.

---

Recommendation

APPROVE - Clean implementation that correctly reflects the DC Code amendment.

🤖 Generated with Claude Code