fix: record delete operations

src/main/java/io/ib67/sfcraft/JustBackupMod.java

@@ -129,6 +129,12 @@ public class JustBackupMod implements ModInitializer, FileWatcherThread.Listener
         if (subject != null) subject.addChanged(file);
     }
 
+    @Override
+    public void onDelete(String subjectName, Path file) {
+        var subject = backupSubjects.get(subjectName);
+        if (subject != null) subject.addDeleted(file);
+    }
+
     @Override
     public void onOverflow(String subjectName) {
         var subject = backupSubjects.get(subjectName);