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The May-built OSHA distance library (minimum_distances.go, 29 CFR 1910, US public domain) was dead code — zero callers, no route, no test, while the mm values that actually appear in measures are independent hand-prose (some carrying ISO 13854/13857 values, not OSHA). This surfaces it without touching the measures response contract: - GET /iace/minimum-distances (+ ?measure_id=) returns the distances, the curated measure→distance link table and the licensing note. - AllMeasureDistanceLinks/MinimumDistancesForMeasure resolve only the defensible links (M600 value_source; M254/M065 public-domain crossref to ISO), with the relation made explicit so the join stays honest. - architecture.go lists the OSHA library so it shows in the audit explainer. - Tests: inch→mm conversion + license completeness, link integrity, and a consistency test pinning that a value_source measure's prose still matches the OSHA source (codifies the audit finding as a regression gate). Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>