feat(storage): add comprehensive tests for StorageManager with memory, filesystem, and custom function backends

feat(email): implement EmailSendJob class for robust email delivery with retry logic and MX record resolution

feat(mail): restructure mail module exports for simplified access to core and delivery functionalities

ts/mail/core/index.ts

@@ -1,8 +1,3 @@
-/**
- * Mail core module
- * Email classes, validation, templates, and bounce management
- */
-
 // Core email components
 export * from './classes.email.ts';
 export * from './classes.emailvalidator.ts';