PR #760 added a second UCDP implementation block (HTTP relay handler)
that redeclared const UCDP_PAGE_SIZE, UCDP_VIOLENCE_TYPE_MAP, and
functions ucdpFetchPage/ucdpDiscoverVersion already declared by the
Redis seeder block — causing SyntaxError on startup and crash-loop.
Rename relay-specific identifiers with RELAY prefix; shared constants
(UCDP_PAGE_SIZE, UCDP_TRAILING_WINDOW_MS) are reused from block 1.