Improve SSI asset imputation and calibration targets

[MaxGhenis]

Fixes #1096

Summary

• remove SSI participation from liquid asset imputation predictors and avoid disability predictors
• add comparable income and household predictors for SIPP/CPS liquid asset imputation
• add SSA December 2024 SSI recipient count targets to legacy loss, DB ETL, and target config
• preserve exact comma-joined domain filtering while allowing single-domain filters like ssi to find multi-constraint strata such as age,ssi

Verification

• uv run pytest -q tests/unit/calibration/test_source_impute.py tests/unit/test_etl_national_targets.py tests/unit/calibration/test_loss_targets.py tests/unit/calibration/test_unified_matrix_builder.py tests/unit/calibration/test_target_config.py tests/unit/test_etl_irs_soi_overlay.py::test_load_national_geography_ctc_agi_targets_creates_agi_domain_strata tests/unit/datasets/test_sipp_monthcode_filter.py tests/unit/datasets/test_sipp_tip_columns.py
• uv run make lint
• $cycle read-only review loop completed with no actionable findings on the final pass

Not run

• full end-to-end calibration pipeline
• SIPP donor asset model retraining/download validation