f83867b dropped seeding new PDS cursors from the relay's listHosts seq. the startup snapshot is taken before the crawler runs, so a host started from it also covers commits made between a repo's backfill and the host's jittered first connect, which a live tail would lose. unlike the old seeding this only fills in a missing cursor: a stored one, the -1 live tail marker, and a running ingestor's in-memory one all win.