fix(server): propagate watch-list cancellation; doc + test gaps (Server-051..053)

src/ZB.MOM.WW.MxGateway.Server/Alarms/AlarmWatchListResolver.cs

@@ -66,11 +66,13 @@ public sealed class AlarmWatchListResolver : IAlarmWatchListResolver
             {
                 rows = await _repository.GetAlarmAttributesAsync(cancellationToken).ConfigureAwait(false);
             }
-            catch (Exception ex)
+            catch (Exception ex) when (ex is not OperationCanceledException)
             {
                 // Discovery being unavailable must not crash the resolver: log and
                 // continue with an empty discovery set. The caller decides what to
-                // do with the (possibly config-only) result.
+                // do with the (possibly config-only) result. Cancellation is the one
+                // exception — an OperationCanceledException propagates per the
+                // IAlarmWatchListResolver contract so the caller unwinds promptly.
                 _logger.LogWarning(
                     ex,
                     "Galaxy Repository alarm-attribute discovery failed; continuing with configuration-only watch-list.");

src/ZB.MOM.WW.MxGateway.Server/Configuration/AlarmFallbackOptions.cs

@@ -86,7 +86,10 @@ public sealed class AlarmDiscoveryOptions
     public string[] IncludeAttributes { get; init; } = Array.Empty<string>();
 
     /// <summary>
-    ///     Attribute paths to exclude from the Repository-derived poll list.
+    ///     Attribute paths to remove from the merged poll list (case-insensitive).
+    ///     The exclude runs after the Repository-derived rows and the explicit
+    ///     <see cref="IncludeAttributes"/> entries are combined, so an exclude that
+    ///     matches an explicit include suppresses it too — excludes win.
     ///     Ignored when <see cref="UseGalaxyRepository"/> is <c>false</c>.
     ///     Default empty.
     /// </summary>