persist_recover's local snapshot load passed NULL for out_entities_restored,
so a rolling-upgrade restart against a pre-feature checkpoint had no
observability parity with the wire receive path's (task 6.1) INFO log.
Mirror the same conditional logging here; no behavior change, WAL replay
in Step 3 still applies unconditionally either way.
Live-verified in a 3-node cluster: planted a hand-crafted 16-byte legacy
sentinel as ctrl-1's own checkpoint file, restarted all 3 — no crash, INFO
log fired, ctrl-1 was elected primary serving the full 37-job list, and
walcompare confirmed all 3 members' committed prefixes (LSN 1..49) are
byte-identical.