feat: Add breakdown_labels metadata for range() dimensions

[anth-volk]

Summary

Requires PolicyEngine/policyengine.py#209. Add breakdown_labels metadata to parameters with range() dimensions to provide semantic labels for numeric breakdown dimensions.

This enables human-readable labels like "Household size 3" instead of raw "3".

Updated parameters (25 files):

• SNAP: max_allotment, income deductions standard
• IL AABD utility params (7 files): bottled_gas, coal, cooking_fuel, electricity, fuel_oil, metered_gas, water
• VT renter credit (3 files): fair_market_rent, income_limit_ami (30%, 50%)
• DC LIHEAP (2 files): electricity, gas
• NC SCCA: childcare_market_rates
• IRS: state_sales_tax_table/tax
• ACA: state_rating_area_cost
• OR: WFHDC credit match
• State TANF/benefits: DC, MN MFIP, UT FEP (2), MO, AR TEA, RI Works

Test plan

• Parameters load correctly with new metadata
• Labels generate correctly when used with policyengine.py changes

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.90%. Comparing base (dff5637) to head (f321027).
⚠️ Report is 48 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7126      +/-   ##
==========================================
- Coverage   76.71%   70.90%   -5.82%     
==========================================
  Files        3665     3666       +1     
  Lines       52702    52712      +10     
  Branches      263      263              
==========================================
- Hits        40432    37377    -3055     
- Misses      12244    15335    +3091     
+ Partials       26        0      -26     

Flag	Coverage Δ
unittests	70.90% <ø> (-5.82%)	⬇️

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[hua7450]

@PavelMakarchuk what do you think about this breakdown_labels ?

[anth-volk]

@PavelMakarchuk what do you think about this breakdown_labels ?

Sorry, perhaps I should've provided some context. The PR that I closed that had one type of fix for each missing label case also had this. I ran it by Pavel as a solution to the fact that we can't directly label range(x,y) breakdown params. At the time, he was supportive, but obviously happy to wait for him to approve this PR.