Report unread bytes and round-trip through JSON text in test czones

The CZone test now flags any record the parser does not read to the
end and passes the JSON through json.dumps/loads, as unpack and pack
do, before rebuilding the binary.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

mbEditorPro2.0/mbEditorPro.py

@@ -295,7 +295,10 @@ def test_czones():
         arc_out = ArcZone()
 
         arc_in.load_binary(in_stream)
-        parsed = arc_in.save_json()
+        unread = len(data) - in_stream.buffer.tell()
+        if unread:
+            print(res_id, 'unread bytes:', unread)
+        parsed = json.loads(json.dumps(arc_in.save_json()))
         arc_out.load_json(parsed)
         arc_out.save_binary(out_stream)
         try: