Expand XML docs across bridge and test code

src/ZB.MOM.WW.LmxOpcUa.Host/GalaxyRepository/ChangeDetectionService.cs

@@ -19,9 +19,22 @@ namespace ZB.MOM.WW.LmxOpcUa.Host.GalaxyRepository
         private CancellationTokenSource? _cts;
         private DateTime? _lastKnownDeployTime;
 
+        /// <summary>
+        /// Occurs when a new Galaxy deploy timestamp indicates the OPC UA address space should be rebuilt.
+        /// </summary>
         public event Action? OnGalaxyChanged;
+
+        /// <summary>
+        /// Gets the last deploy timestamp observed by the polling loop.
+        /// </summary>
         public DateTime? LastKnownDeployTime => _lastKnownDeployTime;
 
+        /// <summary>
+        /// Initializes a new change detector for Galaxy deploy timestamps.
+        /// </summary>
+        /// <param name="repository">The repository used to query the latest deploy timestamp.</param>
+        /// <param name="intervalSeconds">The polling interval, in seconds, between deploy checks.</param>
+        /// <param name="initialDeployTime">An optional deploy timestamp already known at service startup.</param>
         public ChangeDetectionService(IGalaxyRepository repository, int intervalSeconds, DateTime? initialDeployTime = null)
         {
             _repository = repository;
@@ -29,6 +42,9 @@ namespace ZB.MOM.WW.LmxOpcUa.Host.GalaxyRepository
             _lastKnownDeployTime = initialDeployTime;
         }
 
+        /// <summary>
+        /// Starts the background polling loop that watches for Galaxy deploy changes.
+        /// </summary>
         public void Start()
         {
             _cts = new CancellationTokenSource();
@@ -36,6 +52,9 @@ namespace ZB.MOM.WW.LmxOpcUa.Host.GalaxyRepository
             Log.Information("Change detection started (interval={Interval}s)", _intervalSeconds);
         }
 
+        /// <summary>
+        /// Stops the background polling loop.
+        /// </summary>
         public void Stop()
         {
             _cts?.Cancel();
@@ -88,6 +107,9 @@ namespace ZB.MOM.WW.LmxOpcUa.Host.GalaxyRepository
             }
         }
 
+        /// <summary>
+        /// Stops the polling loop and disposes the underlying cancellation resources.
+        /// </summary>
         public void Dispose()
         {
             Stop();