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.Commons/Interfaces/Transport/IBundleImporter.cs

@@ -10,6 +10,7 @@ public interface IBundleImporter
     /// <param name="bundleStream">Stream containing the bundle zip archive.</param>
     /// <param name="passphrase">Optional passphrase for decrypting an encrypted bundle.</param>
     /// <param name="ct">Cancellation token.</param>
+    /// <returns>A task that resolves to session metadata for the loaded bundle.</returns>
     Task<BundleSession> LoadAsync(Stream bundleStream, string? passphrase, CancellationToken ct = default);
 
     /// <summary>
@@ -17,6 +18,7 @@ public interface IBundleImporter
     /// </summary>
     /// <param name="sessionId">Session id returned by <see cref="LoadAsync"/>.</param>
     /// <param name="ct">Cancellation token.</param>
+    /// <returns>A task that resolves to a per-artifact import preview with conflict details.</returns>
     Task<ImportPreview> PreviewAsync(Guid sessionId, CancellationToken ct = default);
 
     /// <summary>
@@ -26,6 +28,7 @@ public interface IBundleImporter
     /// <param name="resolutions">Per-artifact conflict resolutions from the preview step.</param>
     /// <param name="user">Username of the operator performing the import, stamped in audit rows.</param>
     /// <param name="ct">Cancellation token.</param>
+    /// <returns>A task that resolves to the result of the committed import transaction.</returns>
     Task<ImportResult> ApplyAsync(
         Guid sessionId,
         IReadOnlyList<ImportResolution> resolutions,