Map SOI itemized deduction facts

[MaxGhenis]

Summary

• maps new Arch SOI Table 2.1 itemized-deduction fact concepts into Microplex-US target variables
• skips SOI total state/local taxes because it includes personal property taxes outside PolicyEngine's federal SALT input definition
• normalizes Arch's itemized-deductions source domain to PolicyEngine's tax_unit_itemizes target-cell domain for coverage matching

Coverage

• broad PE-native coverage artifact: /Users/maxghenis/CosilicoAI/microplex-us/artifacts/arch_soi_table_2_1_itemized_details_20260528/pe_native_broad_2024_coverage_with_itemized_details_latest_sources_v2.json
• broad coverage: 164 / 189, up from 161 / 189
• newly covered cells: charitable_deduction, interest_deduction, deductible_mortgage_interest
• source-backed coverage artifact: /Users/maxghenis/CosilicoAI/microplex-us/artifacts/arch_soi_table_2_1_itemized_details_20260528/pe_native_broad_source_backed_2024_coverage_with_itemized_details_latest_sources_v2.json
• source-backed coverage: 164 / 174

Tests

• /Users/maxghenis/.local/bin/uv run ruff check src/microplex_us/targets/arch.py tests/targets/test_arch_facts.py tests/targets/test_arch.py
• /Users/maxghenis/.local/bin/uv run --extra dev --extra policyengine python -m pytest tests/targets -q