fix: Add signal_date definition from DataFrame in t_sunnyband.py

src/screener/t_sunnyband.py

@@ -250,6 +250,8 @@ def run_sunny_scanner(min_price: float, max_price: float, min_volume: int, portf
                             )
                             if position['shares'] > 0:
                                 # Update signal data with proper stop loss calculation
+                                # Get signal date from latest data point
+                                signal_date = df.iloc[-1]['date']
                                 signal_data = {
                                     'ticker': ticker,
                                     'entry_price': current_price,