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

modules/bot/python/nnue.py

@@ -131,12 +131,17 @@ def train_interactive():
     num_games = 500000
 
     if use_existing:
-        positions_file = Prompt.ask("Enter path to positions file")
+        positions_file = Prompt.ask("Enter path to positions file", default=str(get_data_dir() / "positions.txt"))
     else:
         num_games = int(Prompt.ask("Number of games to generate", default="500000"))
 
+    use_existing_labels = Confirm.ask("Use existing labels file?", default=False)
+    labels_file = None
+    if use_existing_labels:
+        labels_file = Prompt.ask("Enter path to labels file", default=str(get_data_dir() / "training_data.jsonl"))
+
     # Stockfish path
-    default_stockfish = os.environ.get("STOCKFISH_PATH", "/usr/games/stockfish")
+    default_stockfish = os.environ.get("STOCKFISH_PATH", "/usr/bin/stockfish")
     stockfish_path = Prompt.ask("Stockfish path", default=default_stockfish)
 
     # Training parameters
@@ -180,20 +185,27 @@ def train_interactive():
                 console.print(f"[red]✗ Positions file not found: {positions_file}[/red]")
                 return
 
-        # Label positions
-        console.print("\n[bold cyan]Step 2: Labeling Positions[/bold cyan]")
-        positions_file = data_dir / "positions.txt"
-        output_file = data_dir / "training_data.jsonl"
-        success = label_positions_with_stockfish(
-            str(positions_file),
-            str(output_file),
-            stockfish_path,
-            depth=12
-        )
-        if not success:
-            console.print("[red]✗ Position labeling failed[/red]")
-            return
-        console.print(f"[green]✓ Positions labeled[/green]")
+        if not use_existing_labels:
+            # Label positions
+            console.print("\n[bold cyan]Step 2: Labeling Positions[/bold cyan]")
+            positions_file = data_dir / "positions.txt"
+            output_file = data_dir / "training_data.jsonl"
+            success = label_positions_with_stockfish(
+                str(positions_file),
+                str(output_file),
+                stockfish_path,
+                depth=12
+            )
+            if not success:
+                console.print("[red]✗ Position labeling failed[/red]")
+                return
+            console.print(f"[green]✓ Positions labeled[/green]")
+        else:
+            console.print("\n[bold cyan]Step 2: Loading Existing Labels[/bold cyan]")
+            output_file = labels_file
+            if not Path(output_file).exists():
+                console.print(f"[red]✗ Labels file not found: {output_file}[/red]")
+                return
 
         # Train model
         console.print("\n[bold cyan]Step 3: Training Model[/bold cyan]")