feat: Enhance backend with request/SQL logging via morgan/winston and fix frontend by correctly rendering email Markdown content using the 'marked' library.

backend/logger.js

@@ -0,0 +1,29 @@
+const winston = require('winston');
+
+const logger = winston.createLogger({
+  level: 'info',
+  format: winston.format.combine(
+    winston.format.timestamp({
+      format: 'YYYY-MM-DD HH:mm:ss'
+    }),
+    winston.format.errors({ stack: true }),
+    winston.format.splat(),
+    winston.format.json()
+  ),
+  defaultMeta: { service: 'user-service' },
+  transports: [
+    new winston.transports.File({ filename: 'error.log', level: 'error' }),
+    new winston.transports.File({ filename: 'combined.log' })
+  ]
+});
+
+if (process.env.NODE_ENV !== 'production') {
+  logger.add(new winston.transports.Console({
+    format: winston.format.combine(
+      winston.format.colorize(),
+      winston.format.simple()
+    )
+  }));
+}
+
+module.exports = logger;