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/RouteHelper.cs

@@ -53,6 +53,7 @@ public class RouteHelper
     /// requires.
     /// </summary>
     /// <param name="deadlineToken">The executing method's timeout cancellation token to inherit for routed calls.</param>
+    /// <returns>A new <see cref="RouteHelper"/> inheriting the given deadline token.</returns>
     public RouteHelper WithDeadline(CancellationToken deadlineToken) =>
         new(_instanceLocator, _instanceRouter, deadlineToken, _parentExecutionId);
 
@@ -66,6 +67,7 @@ public class RouteHelper
     /// script context.
     /// </summary>
     /// <param name="parentExecutionId">The inbound request's execution id to stamp as the spawning parent on routed calls, or null for non-routed runs.</param>
+    /// <returns>A new <see cref="RouteHelper"/> carrying the given parent execution id.</returns>
     public RouteHelper WithParentExecutionId(Guid? parentExecutionId) =>
         new(_instanceLocator, _instanceRouter, _deadlineToken, parentExecutionId);
 
@@ -73,6 +75,7 @@ public class RouteHelper
     /// Creates a route target for the specified instance.
     /// </summary>
     /// <param name="instanceCode">The unique code of the instance to route calls to.</param>
+    /// <returns>A <see cref="RouteTarget"/> bound to the specified instance.</returns>
     public RouteTarget To(string instanceCode)
     {
         return new RouteTarget(
@@ -125,6 +128,7 @@ public class RouteTarget
     /// <param name="scriptName">Name of the script to call on the remote instance.</param>
     /// <param name="parameters">Optional parameters passed to the script; may be a dictionary or anonymous object.</param>
     /// <param name="cancellationToken">Optional cancellation token; defaults to the method deadline when not supplied.</param>
+    /// <returns>A task that resolves to the remote script's return value, or null.</returns>
     public async Task<object?> Call(
         string scriptName,
         object? parameters = null,
@@ -158,6 +162,7 @@ public class RouteTarget
     /// </summary>
     /// <param name="attributeName">Name of the attribute to read.</param>
     /// <param name="cancellationToken">Optional cancellation token; defaults to the method deadline.</param>
+    /// <returns>A task that resolves to the attribute value, or null if the key is absent.</returns>
     public async Task<object?> GetAttribute(
         string attributeName,
         CancellationToken cancellationToken = default)
@@ -171,6 +176,7 @@ public class RouteTarget
     /// </summary>
     /// <param name="attributeNames">Names of the attributes to read.</param>
     /// <param name="cancellationToken">Optional cancellation token; defaults to the method deadline.</param>
+    /// <returns>A task that resolves to a map of attribute names to their current values.</returns>
     public async Task<IReadOnlyDictionary<string, object?>> GetAttributes(
         IEnumerable<string> attributeNames,
         CancellationToken cancellationToken = default)
@@ -205,6 +211,7 @@ public class RouteTarget
     /// <param name="attributeName">Name of the attribute to write.</param>
     /// <param name="value">Value to set on the attribute.</param>
     /// <param name="cancellationToken">Optional cancellation token; defaults to the method deadline.</param>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     public async Task SetAttribute(
         string attributeName,
         string value,
@@ -220,6 +227,7 @@ public class RouteTarget
     /// </summary>
     /// <param name="attributeValues">Map of attribute names to values to write.</param>
     /// <param name="cancellationToken">Optional cancellation token; defaults to the method deadline.</param>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     public async Task SetAttributes(
         IReadOnlyDictionary<string, string> attributeValues,
         CancellationToken cancellationToken = default)