Add state IRS SOI source packages

[MaxGhenis]

Summary

• add state-level IRS SOI Historic Table 2 source packages for AGI-by-state/AGI-stub and EITC-by-state totals
• add the 2022 EITC-by-AGI-and-qualifying-children source package from SOI Table 2.5
• expand the default Arch bundle to 12 SOI packages and 1,643 facts across national plus state geographies

Verification

• uv run ruff check arch db tests
• uv run pytest tests/test_arch_bundle.py tests/test_arch_source_package.py tests/test_arch_suite.py -q
• uv build --wheel --out-dir /tmp/arch-local-soi-dist plus wheel package-data inspection

Notes

This follows PR #8 and targets the Microplex latest-loss gaps around state_agi_distribution and EITC shape. I intentionally left the sample congressional-district package out because the current spec only emits 9 facts from selected rows and is not yet enough to justify the 7.4 MB CSV in this production slice.