docs: complete XML doc coverage (returns, summaries, inheritdoc)

Resolve all 622 issues flagged by the enhanced CommentChecker: add missing
<returns> tags (incl. the standard phrasing on non-generic Task methods),
add missing <summary> tags, and replace misused/redundant <inheritdoc/> on
members that override or implement nothing with real documentation.
Documentation-only — no behavior change; solution builds clean.

src/ZB.MOM.WW.ScadaBridge.StoreAndForward/ServiceCollectionExtensions.cs

@@ -11,6 +11,7 @@ public static class ServiceCollectionExtensions
     /// Registers Store-and-Forward services including storage, the delivery service, and the replication service.
     /// </summary>
     /// <param name="services">The service collection to register into.</param>
+    /// <returns>The same <paramref name="services"/> collection, for chaining.</returns>
     public static IServiceCollection AddStoreAndForward(this IServiceCollection services)
     {
         services.AddSingleton<StoreAndForwardStorage>(sp =>
@@ -71,6 +72,7 @@ public static class ServiceCollectionExtensions
     /// Registers Store-and-Forward Akka actor bindings. Actor creation is handled by the Host during actor system startup.
     /// </summary>
     /// <param name="services">The service collection to register into.</param>
+    /// <returns>The same <paramref name="services"/> collection, for chaining.</returns>
     public static IServiceCollection AddStoreAndForwardActors(this IServiceCollection services)
     {
         // Akka actor registration handled by Host component during actor system startup