Critical Comparison Layer Ingest Audit

Created the first regulatory-limit-versus-field-finding comparison layer for HMTc review.

Added

• Machine-readable regulatory limits: data/evidence/regulatory_limits.csv
• Product crosswalk: data/evidence/product_regulatory_crosswalk.csv
• FDA formula sample extraction: data/evidence/category1_formula_special_survey_samples.csv
• FDA formula summary extraction: data/evidence/category1_formula_concentration_summary.csv
• Cross-category wiki hub: regulatory-crosswalk-field-findings
• FDA regulation nodes for processed baby-food lead, infant rice-cereal inorganic arsenic, apple-juice inorganic arsenic, draft juice lead, Juice HACCP lead, and bottled-water lead.

Handling Rules

• Regulatory values were kept separate from field findings and from HMTc candidate limits.
• Draft FDA juice lead values were marked as draft and not for implementation.
• Formula occurrence findings were not compared to processed-baby-food action levels because no matched FDA formula action level was loaded.
• FSA/Fera product and ingredient occurrence evidence remains comparison-blocked until structured table extraction preserves analyte species, basis, units, LoD/LoQ flags, and matrix routing.