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.Transport/Import/BundleImporter.cs

@@ -79,6 +79,7 @@ public sealed class BundleImporter : IBundleImporter
     /// <param name="encryptor">Handles AES-256-GCM decryption of encrypted bundles.</param>
     /// <param name="entitySerializer">Deserializes entity DTOs from bundle content.</param>
     /// <param name="sessionStore">In-memory session store for loaded bundle state.</param>
+    /// <param name="unlockRateLimiter">Rate limiter for passphrase unlock attempts per client IP.</param>
     /// <param name="options">Transport configuration options.</param>
     /// <param name="timeProvider">Abstracted time provider for testability.</param>
     /// <param name="templateRepo">Template engine repository for diff and apply.</param>

src/ZB.MOM.WW.ScadaBridge.Transport/Import/BundleSessionEvictionService.cs

@@ -21,6 +21,11 @@ internal sealed class BundleSessionEvictionService : BackgroundService
     private readonly IBundleSessionStore _sessionStore;
     private readonly ILogger<BundleSessionEvictionService> _logger;
 
+    /// <summary>
+    /// Initializes a new instance of <see cref="BundleSessionEvictionService"/>.
+    /// </summary>
+    /// <param name="sessionStore">The bundle session store to sweep for expired sessions.</param>
+    /// <param name="logger">Logger for sweep diagnostics.</param>
     public BundleSessionEvictionService(
         IBundleSessionStore sessionStore,
         ILogger<BundleSessionEvictionService> logger)
@@ -29,6 +34,7 @@ internal sealed class BundleSessionEvictionService : BackgroundService
         _logger = logger ?? throw new ArgumentNullException(nameof(logger));
     }
 
+    /// <inheritdoc />
     protected override async Task ExecuteAsync(CancellationToken stoppingToken)
     {
         while (!stoppingToken.IsCancellationRequested)

src/ZB.MOM.WW.ScadaBridge.Transport/Import/BundleUnlockRateLimiter.cs

@@ -122,6 +122,8 @@ public sealed class BundleUnlockRateLimiter
     /// within the trailing window. Primarily for tests / diagnostics; not part of the
     /// hot-path.
     /// </summary>
+    /// <param name="clientKey">Opaque caller identifier — typically the remote IP.</param>
+    /// <returns>The number of recorded attempts for the key that still fall within the trailing window.</returns>
     public int GetAttemptCount(string clientKey)
     {
         ArgumentException.ThrowIfNullOrWhiteSpace(clientKey);
@@ -150,6 +152,7 @@ public sealed class BundleUnlockRateLimiter
     /// </summary>
     private sealed class AttemptBucket
     {
+        /// <summary>Ordered queue of attempt timestamps within the current trailing window.</summary>
         public Queue<DateTimeOffset> Timestamps { get; } = new();
     }
 }