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.AuditLog/Site/Telemetry/NoOpSiteStreamAuditClient.cs

@@ -7,9 +7,8 @@ namespace ZB.MOM.WW.ScadaBridge.AuditLog.Site.Telemetry;
 /// <see cref="ZB.MOM.WW.ScadaBridge.AuditLog.ServiceCollectionExtensions.AddAuditLog"/>.
 /// It is a no-op binding for composition roots that have no
 /// <c>SiteCommunicationActor</c> — central and test roots. Site roles override
-/// it in the Host with the ClusterClient-based
-/// <see cref="ClusterClientSiteAuditClient"/>, which actually forwards audit
-/// telemetry to central.
+/// it in the Host with <see cref="SiteCommunicationAuditClient"/>, which
+/// actually forwards audit telemetry to central.
 /// </summary>
 /// <remarks>
 /// <para>
@@ -33,7 +32,7 @@ public sealed class NoOpSiteStreamAuditClient : ISiteStreamAuditClient
     {
         ArgumentNullException.ThrowIfNull(batch);
         // Empty ack — no EventIds will be flipped to Forwarded, so rows stay
-        // Pending until the real ClusterClientSiteAuditClient (or a test stub)
+        // Pending until the real SiteCommunicationAuditClient (or a test stub)
         // takes over.
         return Task.FromResult(EmptyAck);
     }
@@ -45,7 +44,7 @@ public sealed class NoOpSiteStreamAuditClient : ISiteStreamAuditClient
         // Empty ack — same rationale as IngestAuditEventsAsync. The site still
         // writes the audit + tracking rows to its SQLite stores authoritatively;
         // central-side state only materialises once the real
-        // ClusterClientSiteAuditClient (or a test stub) is wired in.
+        // SiteCommunicationAuditClient (or a test stub) is wired in.
         return Task.FromResult(EmptyAck);
     }
 }