Apply Vermont Act 169 (2026) renter credit changes

[DTrim99]

What this does

Applies the 2026 Vermont Act 169 (H.949) changes to the renter credit (32 V.S.A. § 6066(b)).

For #8748.

Changes (effective by claim year)

Parameter	2026 (current)	2027 (Act 169 Secs. 8–9)	2028+ (Act 169 Secs. 10–11)
fmr_rate (renter credit % of fair market rent)	10%	12.5%	10% (reverts)
max_credit (new — statutory cap)	$2,500	$3,250	$2,500 (reverts)

• fmr_rate.yaml: added 2027-01-01: 0.125 and 2028-01-01: 0.1.
• max_credit.yaml (new): the § 6066(b)(1) statutory cap, previously unmodeled, now applied via min_(credit, max_credit) in vt_renter_credit.
• The cap is non-binding under Vermont's FMR schedule (FMR × 12 × rate stays below both $2,500 and $3,250), so it has no effect on current results; it is modeled for faithfulness and future-proofing.

Tests

Added claim-year cases 2026/2027/2028 for a full-credit renter: 2026 = $1,692 (10%) → 2027 = $2,115 (12.5%, exactly 1.25×) → 2028 = $1,692 (reverts). All 10 renter-credit tests pass locally (py 3.11); the existing 7 are unchanged (cap non-binding).

Statute-update check (requested)

The codified 32 V.S.A. § 6066 is not yet updated to reflect Act 169 — the live statute still shows $2,500 / 10% and the $47,000/$90,000 property thresholds. Parameter references therefore cite the session law (2026 Vt. Acts No. 169 / H.949) with #page= anchors, not the permanent statute.

Scope / deferred

The homestead property tax credit (§ 6066(a)) is not modeled in PolicyEngine and is deferred (tracked in #8748). Building it requires property-bill inputs the household model does not currently carry — the housesite education/municipal tax split, equalized (CLA-adjusted) housesite value, and the per-town § 5401(13)(B) education spending adjustment. This PR intentionally covers only the renter-credit (§ 6066(b)) changes.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (194d129) to head (5a08fad).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##              main     #8749    +/-   ##
==========================================
  Coverage   100.00%   100.00%            
==========================================
  Files           11         1    -10     
  Lines          171        33   -138     
==========================================
- Hits           171        33   -138     

Flag	Coverage Δ
unittests	100.00% <100.00%> (ø)

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

☔ View full report in Codecov by Harness.
📢 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.