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/Tracking/OperationTrackingStore.cs

@@ -400,6 +400,7 @@ public class OperationTrackingStore : IOperationTrackingStore, IAsyncDisposable,
     /// connection, so a write currently executing a SqliteCommand completes
     /// before the connection is freed.
     /// </summary>
+    /// <returns>A <see cref="ValueTask"/> that completes when all resources have been released.</returns>
     public async ValueTask DisposeAsync()
     {
         if (Interlocked.Exchange(ref _disposeState, 1) != 0)