The #1285 conformance checklist and formal spec described the search
isolation obligation against the Typesense backend that no longer exists. Keep
the obligation intact (search query carries community_id; results never cross
tenants; refetch is (community_id, event_id)) and restate the mechanism in
terms of the Postgres FTS implementation #1321 ships: the events.search_tsv
generated tsvector column, GIN index, community_id filter BitmapAnd-ed with the
@@ probe, and ChannelScope::ChannelLessOnly in place of the __global__ sentinel.
Co-authored-by: Tyler Longwell <tlongwell@block.xyz>
Signed-off-by: Tyler Longwell <tlongwell@block.xyz>