fix(notifier): Add retry mechanism for Telegram timeout errors

- Add exponential backoff retry logic for Telegram notifications
- Handle TimedOut and NetworkError exceptions gracefully
- Add logging for retry attempts and failures
- Prevent booking system crashes due to network timeouts

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/session_notifier.py

@@ -1,8 +1,10 @@
 import smtplib
 import os
 import logging
+import asyncio
 from email.message import EmailMessage
 from telegram import Bot
+from telegram.error import TimedOut, NetworkError
 
 
 class SessionNotifier:
@@ -75,17 +77,34 @@ class SessionNotifier:
             logging.error(f"Failed to send email: {str(e)}")
             raise
 
-    async def send_telegram_notification(self, message):
+    async def send_telegram_notification(self, message, max_retries=3):
         """
         Send a Telegram notification with the given message.
 
         Args:
             message (str): The message content to be sent in the Telegram chat
+            max_retries (int): Maximum number of retry attempts (default: 3)
         """
         # Create a Bot instance with the provided token
         bot = Bot(token=self.telegram_credentials["token"])
-        # Send the message to the specified chat ID and await the result
-        await bot.send_message(chat_id=self.telegram_credentials["chat_id"], text=message)
+
+        for attempt in range(max_retries):
+            try:
+                # Send the message to the specified chat ID and await the result
+                await bot.send_message(chat_id=self.telegram_credentials["chat_id"], text=message)
+                logging.debug("Telegram notification sent successfully")
+                return
+            except (TimedOut, NetworkError) as e:
+                if attempt < max_retries - 1:
+                    wait_time = 2 ** attempt  # Exponential backoff: 1s, 2s, 4s
+                    logging.warning(f"Telegram notification failed (attempt {attempt + 1}/{max_retries}): {str(e)}. Retrying in {wait_time} seconds...")
+                    await asyncio.sleep(wait_time)
+                else:
+                    logging.error(f"Failed to send Telegram notification after {max_retries} attempts: {str(e)}")
+                    raise
+            except Exception as e:
+                logging.error(f"Unexpected error sending Telegram notification: {str(e)}")
+                raise
 
     async def notify_session_booking(self, session_details):
         """