Add snapshot and reconciliation after starting file system watcher to detect changes

Author: windischb

src/Cocoar.FileSystem/ResilientFileSystemMonitor.cs

@@ -305,6 +305,11 @@ private void TryStartFileSystemWatcher()
             _state = MonitorState.Watching;
             StopPollingTimer();
 
+            // Take a fresh snapshot and reconcile to detect any changes that occurred
+            // while we were in polling mode or during the transition
+            var currentSnapshot = Snapshot(_rootPath);
+            Reconcile(currentSnapshot);
+            
             EnqueueEvent(new EventEntry(EventType.ModeChanged, null!, ModeArgs: new ModeChangedEventArgs(WatcherMode.Native, "watcher started")));
         }
         catch (Exception ex)