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/Repositories/SyntheticId.cs

@@ -21,6 +21,7 @@ internal static class SyntheticId
     /// given name using the FNV-1a hash over its UTF-8 bytes.
     /// </summary>
     /// <param name="name">The string to hash into a synthetic integer ID.</param>
+    /// <returns>A deterministic positive 31-bit integer derived from the FNV-1a hash of the name.</returns>
     public static int From(string name)
     {
         var hash = FnvOffsetBasis;