Resolve non-persisted site context

Resolves an address, coordinate, lot, parcel, or polygon input into parcel, jurisdiction, zoning, coverage, and warning metadata without creating a persisted feasibility site. Authentication is optional except for polygon geometry, which requires a Supabase bearer JWT. Parcel owner details and assessment/sale data (selectedParcel.ownershipHint and rawCityData) are returned only to authenticated callers; anonymous responses null those fields. Requests use the LOCATION route bucket behind the PUBLIC_API middleware backstop.