#333: the Cold doc bullet listed four keys, COLD_KEYS has five

memberHerdrSocket was missing from the prose. The #333 worker spotted it and
correctly left it alone as outside its scope.

Fixed by pointing the bullet at COLD_KEYS instead of re-listing its contents,
so the prose and the set cannot drift apart a second time.

fleetd/src/main/java/dev/ltms/fleet/config/ConfigRef.java

@@ -121,10 +121,12 @@ import java.util.function.Supplier;
  *       reload would leave the operator worse off than today. {@link Outcome#split()} names the
  *       key and says which half is which each time, rather than trying to score "how changed" a
  *       mixed key is or handle "both halves changed in one reload" as a special case.</li>
- *   <li><strong>Cold</strong> — cannot change at all under a running daemon: {@code bind:},
- *       {@code herdrSocket:}, {@code broker:} and {@code auth:}. The socket is bound, the broker
+ *   <li><strong>Cold</strong> — cannot change at all under a running daemon. All five of
+ *       {@link #COLD_KEYS}: {@code bind:}, {@code herdrSocket:}, {@code memberHerdrSocket:},
+ *       {@code broker:} and {@code auth:}. The sockets are already connected, the broker
  *       connection is open, and the auth mode decides who may reach the port that is already
- *       listening.</li>
+ *       listening. This bullet omitted {@code memberHerdrSocket:} until fleetd #333 — say "all
+ *       five of COLD_KEYS" rather than re-listing them, so prose and set cannot drift again.</li>
  * </ul>
  *
  * <p><strong>The denominator, measured on 2026-09-04 (fleetd #330; recounted for fleetd #333).</strong>