refactor(comm): retire ClusterClient naming after the gRPC cutover

Phase 4 of the ClusterClient -> gRPC migration deleted the Akka transports
but left the naming behind: `ClusterClientSiteAuditClient` was transport-
agnostic and worked unchanged, so it survived the deletion under a name
that now describes a transport the repo no longer has. Same for a scatter
of doc-comments still framing gRPC as "the new transport" beside an Akka
one that is gone.

Renames it to `SiteCommunicationAuditClient` (and its test file) and
rewrites the stale comments to describe the single transport that exists.
Also tightens CLAUDE.md: drops the self-describing directory listing and
the 27-component enumeration in favour of the non-obvious parts only.

Behaviour-neutral: names and prose only. Recorded as the Phase 4
follow-up in docs/plans/2026-07-22-clusterclient-to-grpc-plan.md.

src/ZB.MOM.WW.ScadaBridge.Communication/Actors/DebugStreamBridgeActor.cs

@@ -94,10 +94,10 @@ public class DebugStreamBridgeActor : ReceiveActor, IWithTimers
     /// <summary>
     /// Initializes the debug stream bridge actor and registers message handlers.
     /// </summary>
-    /// <param name="siteIdentifier">Site identifier for targeting ClusterClient messages and logging.</param>
+    /// <param name="siteIdentifier">Site identifier for targeting site-addressed messages and logging.</param>
     /// <param name="instanceUniqueName">Unique name of the instance whose debug stream is being bridged.</param>
     /// <param name="correlationId">Correlation id for the debug session.</param>
-    /// <param name="centralCommunicationActor">Actor used to forward ClusterClient messages to the site.</param>
+    /// <param name="centralCommunicationActor">Actor used to forward site-addressed messages to the site.</param>
     /// <param name="onEvent">Callback invoked on each received debug event.</param>
     /// <param name="onTerminated">Callback invoked when the stream terminates.</param>
     /// <param name="grpcFactory">Factory for creating gRPC streaming clients.</param>
@@ -124,7 +124,7 @@ public class DebugStreamBridgeActor : ReceiveActor, IWithTimers
         _grpcNodeAAddress = grpcNodeAAddress;
         _grpcNodeBAddress = grpcNodeBAddress;
 
-        // Initial snapshot response from the site (via ClusterClient).
+        // Initial snapshot response from the site.
         // If the site reports InstanceNotFound=true the instance is not
         // deployed there. Under the stream-first lifecycle the gRPC stream
         // was already opened in PreStart, so the not-found path must tear it down