docs(xml): fill missing XML doc comments + strip task-tracking refs across src (fixdocs)

Add missing <summary>/<param>/<returns>/<typeparam> tags and switch
interface implementations to <inheritdoc/> across 106 files; strip
project bookkeeping identifiers (Task NN, #05-TNN, PLAN-04, StoreAndForward-0NN)
from shipped code comments while preserving the descriptive rationale.
Comment-only: zero code-logic lines changed; solution builds 0/0.

Claude-Session: https://claude.ai/code/session_01MtdgwpEeCUn6cUA5f1LMPj

src/ZB.MOM.WW.ScadaBridge.Host/Actors/AkkaHostedService.cs

@@ -83,6 +83,7 @@ public class AkkaHostedService : IHostedService
     /// <param name="clusterOptions">The cluster configuration options.</param>
     /// <param name="communicationOptions">The communication configuration options.</param>
     /// <param name="logger">The logger instance.</param>
+    /// <param name="appLifetime">The host application lifetime; optional so existing construction sites (tests, DI variants) keep working without it.</param>
     public AkkaHostedService(
         IServiceProvider serviceProvider,
         IOptions<NodeOptions> nodeOptions,
@@ -205,7 +206,7 @@ public class AkkaHostedService : IHostedService
             // process must exit so the service supervisor (docker
             // `restart: unless-stopped` / Windows service recovery) restarts it and
             // it rejoins as a fresh incarnation. Without this the node idles forever
-            // with a dead actor system (review 01 underdeveloped #2).
+            // with a dead actor system (review 01 underdeveloped finding).
             system.WhenTerminated.ContinueWith(_ =>
             {
                 if (_stopRequested) return;
@@ -862,7 +863,7 @@ akka {{
             // Standby must be passive: only the active site node runs the S&F
             // delivery sweep. Without this gate BOTH nodes deliver the same
             // replicated Pending rows — systematic duplicate external calls and
-            // DB writes (arch review 02, Stability #2). Re-evaluated per sweep
+            // DB writes (arch review 02, Stability). Re-evaluated per sweep
             // tick so failover resumes delivery within one RetryTimerInterval.
             // IClusterNodeProvider.SelfIsPrimary is the canonical "this node is the
             // oldest Up member (singleton host)" check from the cluster-infrastructure

src/ZB.MOM.WW.ScadaBridge.Host/Actors/CentralSingletonRegistrar.cs

@@ -17,6 +17,17 @@ internal static class CentralSingletonRegistrar
 {
     internal sealed record Handle(IActorRef Manager, IActorRef Proxy);
 
+    /// <summary>
+    /// Creates the <see cref="ClusterSingletonManager"/> and proxy for a central
+    /// cluster singleton under the canonical naming scheme, and registers a
+    /// PhaseClusterLeave drain task that GracefulStops the manager on shutdown.
+    /// </summary>
+    /// <param name="system">The actor system to register the singleton on.</param>
+    /// <param name="name">The singleton's base name (actors are named <c>{name}-singleton</c> / <c>{name}-proxy</c>).</param>
+    /// <param name="singletonProps">The <see cref="Props"/> used to create the singleton's managed actor.</param>
+    /// <param name="logger">Logger used to report drain progress/failures.</param>
+    /// <param name="drainTimeout">Maximum time to wait for the drain task to complete; defaults to 10 seconds.</param>
+    /// <returns>A <see cref="Handle"/> carrying the singleton manager and proxy actor refs.</returns>
     internal static Handle Start(
         ActorSystem system,
         string name,