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.InboundAPI/EndpointExtensions.cs

@@ -53,6 +53,7 @@ public static class EndpointExtensions
 
     /// <summary>Registers the <c>POST /api/{methodName}</c> inbound API endpoint with the active-node gate and body-size filter applied.</summary>
     /// <param name="endpoints">The route builder to add the endpoint to.</param>
+    /// <returns>The same <paramref name="endpoints"/> instance for chaining.</returns>
     public static IEndpointRouteBuilder MapInboundAPI(this IEndpointRouteBuilder endpoints)
     {
         endpoints.MapPost("/api/{methodName}", HandleInboundApiRequest)