Remove temporary ACS WIC assumption after replacement certification

[anth-volk]

Fixes #561

Summary

• Stack on the minimal compatibility fix Temporarily handle missing ACS WIC participation inputs #566 and delete only its temporary ACS missing-WIC assumption.
• Retain ordinary legacy-name mapping and reject missing values for every source.
• Test native current-name participation, unchanged eligibility, strict missing-input failures, and non-mutating validation.
• Add an intentionally failing certification check while the known incomplete ACS-local dataset remains pinned.

Blocked: do not merge yet

Microcosm PolicyEngine/microcosm#1154 must rebuild and publish a complete local-area dataset. Its code repair is PolicyEngine/microcosm#1156; merging that code alone does not publish a replacement. Add the replacement's actual immutable certification to this PR before merging. No replacement pin or hash is fabricated here. The national default remains unchanged.

After #566 merges, rebase and retarget this PR to main. Keep this PR a draft until the replacement is published, certified, and all checks pass.

Validation

• 87 focused mapping and native-input country-model integration tests passed after restacking on the clean fix branch.
• tests/test_acs_wic_replacement.py fails intentionally against the current broken pin; do not skip or relax it.
• Current CI Ruff lint and formatting pass.
• No dataset rebuild/publication, paid compute, service deployment, environment-variable changes, or database changes.