fix(email): add required Date header to outbound mail

tools/send_message_tool.py

@@ -1075,6 +1075,7 @@ async def _send_email(extra, chat_id, message):
     """Send via SMTP (one-shot, no persistent connection needed)."""
     import smtplib
     from email.mime.text import MIMEText
+    from email.utils import formatdate
 
     address = extra.get("address") or os.getenv("EMAIL_ADDRESS", "")
     password = os.getenv("EMAIL_PASSWORD", "")
@@ -1092,6 +1093,7 @@ async def _send_email(extra, chat_id, message):
         msg["From"] = address
         msg["To"] = chat_id
         msg["Subject"] = "Hermes Agent"
+        msg["Date"] = formatdate(localtime=True)
 
         server = smtplib.SMTP(smtp_host, smtp_port)
         server.starttls(context=ssl.create_default_context())