fix: Gmail App Password parameter name in settings controller

- Changed gmail_password to gmail_app_password in request body destructuring
- Matches frontend Settings.jsx which sends gmail_app_password
- Backend still stores as 'gmail_password' key in database (for backward compatibility)

backend/src/controllers/settings.controller.js

@@ -25,7 +25,7 @@ exports.getAllSettings = async (req, res, next) => {
 // Update Gmail settings
 exports.updateGmailSettings = async (req, res, next) => {
   try {
-    const { gmail_user, gmail_password, gmail_from_name } = req.body;
+    const { gmail_user, gmail_app_password, gmail_from_name } = req.body;
 
     if (gmail_user) {
       await Settings.upsert({
@@ -36,10 +36,10 @@ exports.updateGmailSettings = async (req, res, next) => {
       });
     }
 
-    if (gmail_password) {
+    if (gmail_app_password) {
       await Settings.upsert({
         key: 'gmail_password',
-        value: gmail_password,
+        value: gmail_app_password,
         is_encrypted: true,
         description: 'Gmail App Password',
       });