feat(model_selection): add timing for model training and validation processes

code/src/ml/model_selection.py

@@ -117,11 +117,20 @@ def train_and_evaluate_model(
     result = {"model": model_name, "sensor": sensor_label, "success": False}
 
     try:
+        import time
+        start_time = time.time()
+
         # Train the model
         model.fit(x_train, y_train)
 
+        result["elapsed_time_training"] = time.time() - start_time
         try:
+            # Predict on the test set (validation)
+            start_time = time.time()
+    
             y_pred = model.predict(x_test)
+
+            result["elapsed_time_validation"] = time.time() - start_time
             result["y_pred"] = y_pred  # Convert to numpy array
         except Exception as e:
             result["error"] = f"Prediction error: {str(e)}"