warn when val period shorter than projection period

model.py

@@ -1,8 +1,9 @@
 import pandas as pd
 import numpy as np
-from datetime import timedelta
 import matplotlib.pyplot as plt
 import seaborn as sns
+import warnings
+from datetime import timedelta
 from multiprocessing import Pool
 
 
@@ -1079,6 +1080,11 @@ def create_backtest_plot(
     if len(training_df) < 30:  # Require at least 30 days of training data
         raise ValueError("Insufficient training data before backtest date")
 
+    if len(validation_df) < project_days:
+        warnings.warn(
+            f"Validation period ({len(validation_df)} days) shorter than projection period ({project_days} days)"
+        )
+
     # Generate historical projections using only training data
     historical_projections = project_prices(training_df, days_forward=project_days)