feat: enhance email configuration and validation features

- Implemented mutual exclusivity for SSL and TLS options in the email configuration.
- Added comprehensive validation for required fields, port range, email format, and password requirements.
- Updated the backend to support reversible encryption for SMTP passwords, ensuring secure handling of sensitive data.
- Introduced loading states and improved user feedback in the email configuration UI for better user experience.

packages/backend/convex/schema.ts

@@ -471,7 +471,7 @@ export default defineSchema({
     servidor: v.string(), // smtp.gmail.com
     porta: v.number(), // 587, 465, etc.
     usuario: v.string(),
-    senhaHash: v.string(), // senha criptografada
+    senhaHash: v.string(), // senha criptografada reversível (AES-GCM) - necessário para descriptografar e usar no SMTP
     emailRemetente: v.string(),
     nomeRemetente: v.string(),
     usarSSL: v.boolean(),