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.

tests/ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests/Deployment/DebugViewTests.cs

@@ -28,7 +28,7 @@ namespace ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests.Deployment;
 /// <b>Tolerant terminal-state assertion (validation-behavior protocol):</b> whether
 /// <c>Connect</c> reaches a <b>Live</b> badge depends on the owning site returning a
 /// snapshot for the instance. Reading <c>DebugView.razor::Connect</c>: it awaits
-/// <c>DebugStreamService.StartStreamAsync</c> (a ClusterClient snapshot round-trip);
+/// <c>DebugStreamService.StartStreamAsync</c> (a site snapshot round-trip);
 /// on success it flips <c>_connected = true</c> (Live badge + success toast), and on
 /// any exception it surfaces a <c>Connect failed: …</c> error <c>.toast</c>. Either
 /// way <c>_connecting</c> resets, so the click always resolves — it never hangs. The

tests/ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests/Deployment/DebugViewTreeTests.cs

@@ -19,13 +19,13 @@ namespace ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests.Deployment;
 /// and would never appear, so the test mints an instance via the shared
 /// <see cref="DeploymentFixture"/> and drives it to <c>Enabled</c> over the CLI
 /// (<c>instance deploy</c>) before selecting it. The fixture provisions onto the
-/// real, running <c>site-a</c> so the ClusterClient snapshot round-trip resolves
-/// fast (an unknown site has no registered ClusterClient and only times out).
+/// real, running <c>site-a</c> so the snapshot round-trip resolves
+/// fast (an unknown site has no reachable gRPC endpoint and only times out).
 /// </para>
 ///
 /// <para>
 /// <b>Tolerant terminal-state wait, then the tabs/trees assertions</b> — Connect
-/// awaits a ClusterClient snapshot round-trip; on success the page flips to the
+/// awaits a site snapshot round-trip; on success the page flips to the
 /// Live badge and renders the tabbed card, on failure it surfaces a
 /// <c>Connect failed: …</c> <c>.toast</c> (see <c>DebugView.razor::Connect</c>).
 /// The test first waits on a TERMINAL state (Live badge OR error toast) within a

tests/ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests/Deployment/DeploymentFixture.cs

@@ -11,8 +11,8 @@ namespace ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests.Deployment;
 ///
 /// <para>
 /// <b>Why <c>site-a</c> and not a throwaway site:</b> the deploy / enable / disable
-/// actions relay to the owning site over the Akka <c>ClusterClient</c>. An unknown
-/// site identifier has no registered <c>ClusterClient</c>, so the relay only
+/// actions relay to the owning site over the gRPC site command plane. An unknown
+/// site identifier has no reachable gRPC endpoint, so the relay only
 /// resolves on a slow 10-second timeout (and never surfaces a fast failure toast).
 /// To exercise the real action path, the ephemeral instances must therefore live
 /// on a <em>real, running</em> site — <c>site-a</c> — rather than a fixture-created

tests/ZB.MOM.WW.ScadaBridge.CentralUI.PlaywrightTests/SiteCalls/SiteCallsPageTests.cs

@@ -282,8 +282,8 @@ public class SiteCallsPageTests
             // be relayed to the owning site. Unlike the display-only tests above,
             // this one actually relays to the owning site, so the SourceSite must
             // be a *real* site identifier from the running cluster (site-a) and
-            // not the cosmetic "plant-a" label: an unknown site has no registered
-            // ClusterClient, so CentralCommunicationActor drops the envelope
+            // not the cosmetic "plant-a" label: an unknown site has no reachable
+            // gRPC endpoint, so CentralCommunicationActor drops the envelope
             // without replying and the relay only resolves on the 10s inner Ask
             // timeout — too slow for the toast assertion below. Relayed to a live
             // site, the site finds no parked S&F message for this freshly-seeded
@@ -319,7 +319,7 @@ public class SiteCallsPageTests
             // We only assert that an outcome toast appears (exactly one — the
             // single-toast contract), not which one, since the live cluster
             // state determines the outcome. The wait is generous (15s): the
-            // relay round-trips to the site over ClusterClient, and a worst-case
+            // relay round-trips to the site over gRPC, and a worst-case
             // path can sit on the 10s inner relay timeout before the response —
             // and the toast itself auto-dismisses 5s after it appears, so the
             // assertion must catch it inside that window.