feat: enhance nnue.py and train.py with options for existing labels and improved file handling

modules/bot/python/src/train.py

@@ -92,10 +92,14 @@ def find_next_version(base_name="nnue_weights"):
     Looks for nnue_weights_v*.pt files and returns the next version number.
     If no versioned files exist, returns 1.
     """
-    pattern = re.compile(rf"{re.escape(base_name)}_v(\d+)\.pt")
+    base_path = Path(base_name)
+    directory = base_path.parent
+    filename = base_path.name
+
+    pattern = re.compile(rf"{re.escape(filename)}_v(\d+)\.pt")
     versions = []
 
-    for file in Path(".").glob(f"{base_name}_v*.pt"):
+    for file in directory.glob(f"{filename}_v*.pt"):
         match = pattern.match(file.name)
         if match:
             versions.append(int(match.group(1)))