Add ORG-backed hourly wage and union inputs

[MaxGhenis]

Summary

This adds the downstream policyengine-us input variables needed for ORG-backed data:

• hourly_wage
• is_union_member_or_covered

Why

These inputs are populated by the companion policyengine-us-data PR that adds ORG labor-market imputations to CPS and eCPS.

That companion change materially improves the modeled overtime deduction on published eCPS weights:

• 2026 overtime deduction tax expenditure rises from $9.63B to $14.56B
• that is +$4.93B or +51.2%

Caveat: that comparison is on the published eCPS weights with ORG overlaid, not a fully regenerated Enhanced CPS artifact.

Validation

• 2 tests passed for the new input variables
• validation notebook gist: https://gist.github.com/MaxGhenis/634977ffccb65a288f54d602a2244ed9

Companion PR

• policyengine-us-data: adds ORG donor/imputation support and wires the variables into CPS and eCPS
  Add ORG labor-market imputations to CPS and eCPS policyengine-us-data#674

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (edaf7b1) to head (45daf5d).
⚠️ Report is 46 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #7909      +/-   ##
===========================================
+ Coverage   97.26%   100.00%   +2.73%     
===========================================
  Files           5         2       -3     
  Lines          73        14      -59     
  Branches        2         0       -2     
===========================================
- Hits           71        14      -57     
+ Misses          1         0       -1     
+ Partials        1         0       -1     

Flag	Coverage Δ
unittests	100.00% <100.00%> (+2.73%)	⬆️

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