fix: add missing MIMEMultipart import for email alerts

transcription_bot/handlers.py

@@ -44,6 +44,7 @@ def _transcription_log_and_notify_email(action: str, error_details: str):
     try:
         import smtplib
         from email.mime.text import MIMEText
+        from email.mime.multipart import MIMEMultipart
         msg = MIMEMultipart()
         
         default_from = getattr(config, 'DEFAULT_EMAIL_FROM', 'bot@noreply.com')
@@ -182,3 +183,4 @@ async def transcription_handler(msg: Message):
 
 
 
+