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/InboundApiEndpointFilter.cs

@@ -40,6 +40,7 @@ public sealed class InboundApiEndpointFilter : IEndpointFilter
     /// <summary>Applies active-node gating and request body size checks before delegating to the next filter or handler.</summary>
     /// <param name="context">The endpoint filter invocation context containing the HTTP context and arguments.</param>
     /// <param name="next">The next filter or endpoint handler in the pipeline.</param>
+    /// <returns>A value task that resolves to the filter pipeline result, or an error result if gating fails.</returns>
     public async ValueTask<object?> InvokeAsync(
         EndpointFilterInvocationContext context,
         EndpointFilterDelegate next)