data(safety): food-safe flag accuracy — US FEMA-GRAS coverage + restricted-use molecules

[rvnminers-A-and-N]

The food-safe flag has real gaps (spot-checked):

• False negatives — US FEMA GRAS molecules not on the EU/GB Union List are missed, e.g. nootkatone (FEMA GRAS 3166, grapefruit) reads non-food. The check leans on the EU list + a small SAF set.
• False positives — "listed but restricted" molecules read food-safe, e.g. coumarin (banned as a direct flavor additive in the US; restricted in the EU) reads food-listed.

Fix: broaden the food-use reference to include the public FEMA GRAS list (US) and add a restricted/prohibited overlay (coumarin, safrole, estragole, methyleugenol, ...) so the flag reflects usable-as-a-flavor, not merely appears-on-a-list. Ties into the multi-axis safety profile.