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/Middleware/AuditWriteMiddleware.cs

@@ -128,6 +128,7 @@ public sealed class AuditWriteMiddleware
     /// Executes the middleware: captures the request/response bodies and writes an inbound API audit event.
     /// </summary>
     /// <param name="ctx">The current HTTP context.</param>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     public async Task InvokeAsync(HttpContext ctx)
     {
         var sw = Stopwatch.StartNew();
@@ -686,6 +687,7 @@ public sealed class AuditWriteMiddleware
         /// audit copy hit the cap. Returns <c>(null, false)</c> when no bytes
         /// were captured, mirroring the request-body empty contract.
         /// </summary>
+        /// <returns>A tuple of the captured body string (or <c>null</c> if nothing was captured) and a flag indicating whether the cap was exceeded.</returns>
         public (string? body, bool truncated) GetCapturedBody()
         {
             var length = (int)_captured.Length;