feat: wip send mail preview

packages/webapp/src/containers/Sales/Estimates/EstimateSendMailDrawer/EstimateSendMail.schema.ts

@@ -1,3 +1,11 @@
 import * as Yup from 'yup';
 
-export const EstimateSendMailSchema = Yup.object().shape({});
+export const EstimateSendMailSchema = Yup.object().shape({
+  subject: Yup.string().required('Subject is required'),
+  message: Yup.string().required('Message is required'),
+  to: Yup.array()
+    .of(Yup.string().email('Invalid email address'))
+    .required('To address is required'),
+  cc: Yup.array().of(Yup.string().email('Invalid email address')),
+  bcc: Yup.array().of(Yup.string().email('Invalid email address')),
+});