docs(src): add missing XML docs and strip tracking-ID comments

Sweep of 203 source files resolving CommentChecker findings: add
<summary>/<param>/<returns>/<inheritdoc> where missing, and remove
resolved task/issue tracking markers (Tests-NNN, Worker-NNN, Server-NNN,
Task N) from code comments. Comment/doc-only — no logic changes.
Server+Tests build clean under TreatWarningsAsErrors.

src/ZB.MOM.WW.MxGateway.Server/Dashboard/DashboardSnapshotService.cs

@@ -35,7 +35,7 @@ public sealed class DashboardSnapshotService : IDashboardSnapshotService
     // sequence means the breakdown is unchanged and can be reused — keeping the ~1s snapshot tick
     // O(1) for Galaxy. The summary's cheap volatile fields (status, timestamps, last error, counts)
     // are NOT memoized: the library mutates them in place at the same sequence on steady-state ticks
-    // and on refresh failure, so they are copied fresh on every snapshot (see Server-059).
+    // and on refresh failure, so they are copied fresh on every snapshot.
     private GalaxyBreakdownCache? _galaxyBreakdownCache;
 
     /// <summary>Initializes a new instance of the DashboardSnapshotService class.</summary>
@@ -72,10 +72,7 @@ public sealed class DashboardSnapshotService : IDashboardSnapshotService
         _logger = logger ?? NullLogger<DashboardSnapshotService>.Instance;
     }
 
-    /// <summary>
-    /// Gets a current dashboard snapshot of gateway state.
-    /// </summary>
-    /// <returns>Dashboard snapshot.</returns>
+    /// <inheritdoc />
     public DashboardSnapshot GetSnapshot()
     {
         DateTimeOffset generatedAt = _timeProvider.GetUtcNow();
@@ -133,11 +130,7 @@ public sealed class DashboardSnapshotService : IDashboardSnapshotService
 
     private sealed record GalaxyBreakdownCache(long Sequence, GalaxyObjectBreakdown Breakdown);
 
-    /// <summary>
-    /// Watches dashboard snapshots at regular intervals asynchronously.
-    /// </summary>
-    /// <param name="cancellationToken">Cancellation token.</param>
-    /// <returns>Async enumerable of dashboard snapshots.</returns>
+    /// <inheritdoc />
     public async IAsyncEnumerable<DashboardSnapshot> WatchSnapshotsAsync(
         [EnumeratorCancellation] CancellationToken cancellationToken)
     {