docs(xmldoc): fill missing XML docs + strip tracking-ID comments across src

Adds <summary>/<param>/<returns>/<inheritdoc> where missing and removes
project bookkeeping IDs (task/tracking refs) from shipped code comments,
so the docs read cleanly and CommentChecker is quiet except for known
false positives (PLC/protocol terms, event/IEqualityComparer inheritdoc).
Doc/comment-only; no logic changed; solution builds clean.

src/Server/ZB.MOM.WW.OtOpcUa.ControlPlane/Fleet/FleetStatusBroadcaster.cs

@@ -10,7 +10,7 @@ namespace ZB.MOM.WW.OtOpcUa.ControlPlane.Fleet;
 /// <summary>
 /// Admin-role cluster singleton that maintains an in-memory <see cref="FleetStatusChanged"/>
 /// snapshot from cluster membership + reachability events plus per-node heartbeats, and pushes
-/// diffs on the <c>fleet-status</c> DistributedPubSub topic. The SignalR hub layer (Task 49)
+/// diffs on the <c>fleet-status</c> DistributedPubSub topic. The SignalR hub layer
 /// subscribes to that topic and forwards to browser clients.
 ///
 /// Heartbeat staleness: a node we haven't heard from in <see cref="HeartbeatTimeout"/> flips