docs(xmldoc): fill missing XML docs + strip tracking-ID comments across src

Adds <summary>/<param>/<returns>/<inheritdoc> where missing and removes
project bookkeeping IDs (task/tracking refs) from shipped code comments,
so the docs read cleanly and CommentChecker is quiet except for known
false positives (PLC/protocol terms, event/IEqualityComparer inheritdoc).
Doc/comment-only; no logic changed; solution builds clean.

src/Core/ZB.MOM.WW.OtOpcUa.Core.Abstractions/PollGroupEngine.cs

@@ -41,6 +41,7 @@ public sealed class PollGroupEngine : IAsyncDisposable
     /// <summary>Default floor for publishing intervals — matches the Modbus 100 ms cap.</summary>
     public static readonly TimeSpan DefaultMinInterval = TimeSpan.FromMilliseconds(100);
 
+    /// <summary>Constructs the engine with the driver-supplied reader, change callback, and optional interval floor / error sink.</summary>
     /// <param name="reader">Driver-supplied batch reader; snapshots MUST be returned in the same
     ///     order as the input references.</param>
     /// <param name="onChange">Callback invoked per changed tag — the driver forwards to its own
@@ -49,7 +50,7 @@ public sealed class PollGroupEngine : IAsyncDisposable
     ///     per <see cref="DefaultMinInterval"/>.</param>
     /// <param name="onError">Optional error sink — invoked once per caught reader exception (or
     ///     internal contract-violation throw) so the owning driver can route the failure to its
-    ///     health surface (Core.Abstractions-005). Defensive: an <c>onError</c> handler that
+    ///     health surface. Defensive: an <c>onError</c> handler that
     ///     itself throws is silently absorbed so a buggy forwarder cannot crash the poll loop.</param>
     public PollGroupEngine(
         Func<IReadOnlyList<string>, CancellationToken, Task<IReadOnlyList<DataValueSnapshot>>> reader,
@@ -68,6 +69,7 @@ public sealed class PollGroupEngine : IAsyncDisposable
     /// <summary>Register a new polled subscription and start its background loop.</summary>
     /// <param name="fullReferences">The list of tag references to poll.</param>
     /// <param name="publishingInterval">The desired polling interval; will be clamped to the configured minimum.</param>
+    /// <returns>A handle identifying the new subscription, for later use with <see cref="Unsubscribe"/>.</returns>
     public ISubscriptionHandle Subscribe(IReadOnlyList<string> fullReferences, TimeSpan publishingInterval)
     {
         ArgumentNullException.ThrowIfNull(fullReferences);
@@ -138,7 +140,7 @@ public sealed class PollGroupEngine : IAsyncDisposable
             catch (Exception ex) when (!IsFatal(ex))
             {
                 // transient poll error — loop continues, driver health surface logs it
-                // via the supplied onError callback (Core.Abstractions-005).
+                // via the supplied onError callback.
                 ReportError(ex);
             }
         }
@@ -170,7 +172,7 @@ public sealed class PollGroupEngine : IAsyncDisposable
     {
         var snapshots = await _reader(state.TagReferences, ct).ConfigureAwait(false);
 
-        // Core.Abstractions-002: validate the reader contract before indexing. A reader that
+        // Validate the reader contract before indexing. A reader that
         // returns fewer snapshots than references would silently stall the subscription; surface
         // the violation immediately with a descriptive exception instead.
         if (snapshots.Count != state.TagReferences.Count)
@@ -207,6 +209,7 @@ public sealed class PollGroupEngine : IAsyncDisposable
     }
 
     /// <summary>Cancel every active subscription and await all loop tasks. Idempotent.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     public async ValueTask DisposeAsync()
     {
         // Cancel all loops first so they can all start winding down in parallel.
@@ -253,7 +256,7 @@ public sealed class PollGroupEngine : IAsyncDisposable
 
     private sealed record PollSubscriptionHandle(long Id) : ISubscriptionHandle
     {
-        /// <summary>Gets a diagnostic identifier for this subscription.</summary>
+        /// <inheritdoc />
         public string DiagnosticId => $"poll-sub-{Id}";
     }
 }