Remove reported-value model shortcuts

[MaxGhenis]

Summary

• remove model-side short-circuits that substituted reported SNAP, broadband subsidy, and state income tax values for modeled results
• delete the reported-state-income-tax reform and the associated simulation parameter toggles
• update baseline tests to assert reported inputs are ignored, add an explicit SNAP regression, and stop uprating the dead reported fallback channels

Testing

• uv run pytest -q policyengine_us/tests/policy/baseline/gov/usda/snap policyengine_us/tests/policy/baseline/gov/states/tax/income policyengine_us/tests/policy/baseline/household
• uv run ruff check policyengine_us/tools/default_uprating.py policyengine_us/reforms/federal/init.py policyengine_us/reforms/reforms.py policyengine_us/variables/gov/usda/snap/snap.py policyengine_us/variables/household/income/spm_unit/spm_unit_broadband_subsidy.py policyengine_us/variables/gov/states/tax/income/state_income_tax.py policyengine_us/variables/household/expense/tax/spm_unit_state_tax.py policyengine_us/variables/household/income/household/household_state_income_tax.py policyengine_us/tests/test_batched.py

[codecov]

Codecov Report

❌ Patch coverage is 75.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 96.66%. Comparing base (4418878) to head (37c89dd).
⚠️ Report is 25 commits behind head on main.

Files with missing lines	Patch %	Lines
policyengine_us/variables/gov/usda/snap/snap.py	50.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##              main    #7858      +/-   ##
===========================================
- Coverage   100.00%   96.66%   -3.34%     
===========================================
  Files            1        5       +4     
  Lines           21       60      +39     
  Branches         0        2       +2     
===========================================
+ Hits            21       58      +37     
- Misses           0        1       +1     
- Partials         0        1       +1     

Flag	Coverage Δ
unittests	96.66% <75.00%> (-3.34%)	⬇️

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