Donor-impute CPS demographic, occupation, and TTOC features on PUF clones

[MaxGhenis]

Summary

• donor-rematch clone-half is_male, cps_race, is_hispanic, and detailed_occupation_recode using CPS records with similar demographics, geography, and PUF-imputed incomes
• derive treasury_tipped_occupation_code on the CPS half from raw CPS PEIOOCC via an official Census occupation-code crosswalk plus the IRS/Treasury TTOC related-SOC list
• enable clone-half propagation of treasury_tipped_occupation_code when the installed policyengine-us exposes that variable
• rebuild the overtime occupation input flags from the imputed occupation code so FLSA overtime logic uses coherent clone-half inputs
• make stage-2 CPS-only QRF predictors read from the clone half itself when those person-level features have been updated

Why

Right now the PUF clone half keeps donor-copied CPS demographic and occupation labels even after its income profile is replaced by PUF imputation. That weakens subgroup analysis by race/ethnicity/sex and can misclassify occupation-based logic like overtime exemptions.

This PR keeps the existing stage-2 QRF for continuous CPS-only variables, but adds a preceding donor-imputation pass for the categorical CPS features we actually use downstream. It also starts carrying Treasury tipped occupation codes on the CPS side so the rules engine can consume a law-facing occupation input instead of a CPS-specific approximation.

Notes

• The PEIOOCC -> TTOC mapping is an approximation layer in policyengine-us-data, where it belongs. policyengine-us now treats treasury_tipped_occupation_code as an input and does not embed CPS/SOC crosswalk logic.
• Clone-half TTOC rematching is conditional on the installed policyengine-us including treasury_tipped_occupation_code. That keeps this PR CI-compatible until the corresponding policyengine-us change merges.

Testing

• uv run ruff check policyengine_us_data/datasets/cps/tipped_occupation.py policyengine_us_data/datasets/cps/extended_cps.py policyengine_us_data/tests/test_extended_cps.py
• uv run pytest -q policyengine_us_data/tests/test_extended_cps.py
• uv run pytest -q policyengine_us_data/tests/test_calibration/test_puf_impute.py

Interaction notes

• #633 also touches policyengine_us_data/datasets/cps/extended_cps.py, but only for structural mortgage input support. I kept this PR based on main because the logic is otherwise independent; the overlap should be limited to import/generate() context when that PR merges.
• #631 is broader pipeline restructuring and does not change the clone-feature logic added here.