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.Commons/Messages/Management/SchemaLibraryCommands.cs

@@ -2,7 +2,7 @@ namespace ZB.MOM.WW.ScadaBridge.Commons.Messages.Management;
 
 // Schema-library authoring commands. The reusable named JSON-Schema
 // library (the SharedSchema entity + ISharedSchemaRepository) gains its CRUD
-// surface here. These records travel the same HTTP / ClusterClient management
+// surface here. These records travel the same HTTP management
 // boundary as every other *Command and are auto-discovered by reflection in
 // ManagementCommandRegistry (no manual registry entry needed).
 //