added stack trace to some logging

backend/routes/messages.js

@@ -297,6 +297,7 @@ router.post('/', authenticateToken, async (req, res, next) => {
       const reqLogger = logger.withRequestId(req.id);
       reqLogger.error("Failed to send message notification email", {
         error: emailError.message,
+        stack: emailError.stack,
         messageId: message.id,
         receiverId: receiverId
       });
@@ -436,6 +437,7 @@ router.get('/images/:filename',
     const reqLogger = logger.withRequestId(req.id);
     reqLogger.error('Image serve failed', {
       error: error.message,
+      stack: error.stack,
       filename: req.params.filename
     });
     res.status(500).json({ error: 'Failed to load image' });