feat(account): Prioritize dedicated name field for IMAP authentication username #28

Refactor account authentication logic to prioritize the `name` field over the `email` field during the IMAP connection phase.

- The `name` field now serves as the primary IMAP login credential and is no longer treated purely as an optional, descriptive field.
- If the `name` field is empty or unset, the system will fall back to using the full `email` address for authentication.
- This change supports IMAP providers that require a username different from the full email address (e.g., employee ID, specific account name).

web/src/locales/ar.json

@@ -163,6 +163,7 @@
         "emailPlaceholder": "مثال: john.doe@example.com",
         "namePlaceholder": "مثال: john.doe",
         "optional": "اختياري",
+        "nameDescription": "اسم مستخدم اتصال IMAP. اترك هذا الحقل فارغًا إذا كنت تستخدم عنوان بريدك الإلكتروني الكامل كاسم مستخدم للاتصال.",
         "emailCannotBeModified": "لا يمكن تعديل عنوان حساب البريد الإلكتروني أثناء التحرير.",
         "addAccount": "إضافة حساب",
         "updateAccount": "تحديث الحساب",