Reset Georgia income tax rate to constant 5.19%

[DTrim99]

Summary

• Remove premature conditional rate reductions (2026-2028) from Georgia income tax parameters
• Rate is now constant at 5.19% from 2025 onwards

Background

Per statute and the State Auditor's fiscal note of HB1001 (February 24, 2026), the scheduled rate reductions are conditional on revenue targets:

1. Governor's revenue estimate must be at least 3% above current fiscal year
2. Prior fiscal year's revenue must exceed each of the preceding three years
3. Revenue Shortfall Reserve must have sufficient funds

Current budget projections suggest these conditions might not be met until tax years 2029-2030, not 2026-2028 as previously encoded.

Files Changed

• policyengine_us/parameters/gov/states/ga/tax/income/main/single.yaml
• policyengine_us/parameters/gov/states/ga/tax/income/main/joint.yaml
• policyengine_us/parameters/gov/states/ga/tax/income/main/head_of_household.yaml
• policyengine_us/parameters/gov/states/ga/tax/income/main/separate.yaml
• policyengine_us/parameters/gov/states/ga/tax/income/main/surviving_spouse.yaml

Test plan

• Verify GA income tax calculations use 5.19% rate for 2025+
• Confirm no test failures related to GA income tax

Fixes #7697

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.61%. Comparing base (d54fca3) to head (8bcc4c5).
⚠️ Report is 6 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##              main    #7698       +/-   ##
============================================
- Coverage   100.00%   72.61%   -27.39%     
============================================
  Files            1     3906     +3905     
  Lines            9    56370    +56361     
  Branches         0      271      +271     
============================================
+ Hits             9    40934    +40925     
- Misses           0    15416    +15416     
- Partials         0       20       +20     

Flag	Coverage Δ
unittests	72.61% <ø> (-27.39%)	⬇️

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.

[PavelMakarchuk]

LGTM if reference is adjusted

[DTrim99]

CI Note

The failing microsimulation test (employment_income is zero in 2024) is unrelated to this PR's changes.

This PR only modifies Georgia income tax rate parameters (removing 2026-2028 scheduled rate reductions). The failing test checks whether employment_income loads correctly from the enhanced_cps_2024.h5 dataset, which has nothing to do with tax rate parameters.

Evidence that this is not caused by this PR:

• PR #7507 (backdate-in-tanf) passed the same test run minutes before this PR's run
• The test file test_microsim.py has not been modified
• Georgia tax rate parameters cannot affect whether employment income loads from a dataset

This may be a transient CI issue or dataset access problem. Requesting maintainer review.