The verified-sites table's by-state GSI was deleted by its owning
stack (procurement-ingest, audit M-20, 2026-06-03, "0 reads in 30d"),
so the state-listing branch of lookup_site has failed at runtime ever
since. Per the owner's decision, remove the path end-to-end instead
of restoring the GSI: drop the by-state Query from the Lambda, remove
the state parameter from the WO_PO_Lookup lookup_site function schema
(site_code is now required), strip state listings from the agent
instruction, and update the README data-contract table. siteCode
point lookups are unaffected. A stale state parameter from an older
prepared agent version now returns a clear "no longer supported"
message.
Refs: INFRA-180
