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.SiteRuntime/Scripts/ScriptRuntimeContext.cs

@@ -266,6 +266,7 @@ public class ScriptRuntimeContext
     /// </summary>
     /// <param name="attributeName">Name of the attribute to set.</param>
     /// <param name="value">String value to set for the attribute.</param>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     public async Task SetAttribute(string attributeName, string value)
     {
         var correlationId = Guid.NewGuid().ToString();