fix: timezone bugs

alpaca_trader/engine.py

@@ -3,7 +3,7 @@ import sys
 import logging
 import json
 import time
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 from pathlib import Path
 from dotenv import load_dotenv
 import pandas as pd
@@ -561,8 +561,8 @@ def log_missed_signal(timestamp, signal_type, reject_reason, price_at_signal, sy
         if SIGNALS_PATH.exists():
             existing = pd.read_csv(SIGNALS_PATH)
             df = pd.concat([existing, df], ignore_index=True)
-            cutoff_date = datetime.now(EASTERN) - timedelta(days=30)
-            df['timestamp'] = pd.to_datetime(df['timestamp'], format='ISO8601')
+            cutoff_date = datetime.now(timezone.utc) - timedelta(days=30)
+            df['timestamp'] = pd.to_datetime(df['timestamp'], format='mixed', utc=True)
             df = df[df['timestamp'] > cutoff_date]
         
         df.to_csv(SIGNALS_PATH, index=False)