[codex] Add Kansas Lifeline supplement

[daphnehanse11]

Summary

• Adds the Kansas KCC Lifeline supplement parameter for the KUSF phone-service supplement.
• Adds ks_lifeline_supplement, capped by household phone costs.
• Integrates the supplement into the federal Lifeline calculation for KS households.

Closes #8579.

Validation

• uv run --extra dev ruff check policyengine_us/variables/gov/states/ks/kcc/lifeline/ks_lifeline_supplement.py policyengine_us/variables/gov/fcc/lifeline/lifeline.py
• uv run python -m policyengine_core.scripts.policyengine_command test policyengine_us/tests/policy/baseline/gov/states/ks/kcc/lifeline/ks_lifeline_supplement.yaml -c policyengine_us
• uv run python -m policyengine_core.scripts.policyengine_command test policyengine_us/tests/policy/baseline/gov/fcc/lifeline/lifeline.yaml -c policyengine_us

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (fbb907a) to head (30ffbdf).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #8586   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files            3         2    -1     
  Lines           68        40   -28     
  Branches         0         2    +2     
=========================================
- Hits            68        40   -28     

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

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[hua7450]

One non-blocking note: the KCC Lifeline page (https://www.kcc.ks.gov/telecommunications/lifeline) says the Kansas portion is phone-only, and also notes that only $5.25 of the federal discount may be applied to voice-only phone plans. That would make the voice-only maximum $13.02/month, not $17.02/month.

Could you add a short code comment near the Kansas supplement logic noting that voice-only federal discount treatment is not modeled because service type is not represented separately?