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/routing/classes.email.router.ts

@@ -1,11 +1,12 @@
 import * as plugins from '../../plugins.ts';
+import { EventEmitter } from 'node:events';
 import type { IEmailRoute, IEmailMatch, IEmailAction, IEmailContext } from './interfaces.ts';
 import type { Email } from '../core/classes.email.ts';
 
 /**
  * Email router that evaluates routes and determines actions
  */
-export class EmailRouter extends plugins.EventEmitter {
+export class EmailRouter extends EventEmitter {
   private routes: IEmailRoute[];
   private patternCache: Map<string, boolean> = new Map();
   private storageManager?: any; // StorageManager instance
@@ -407,7 +408,7 @@ export class EmailRouter extends plugins.EventEmitter {
       }
       
       const routesData = JSON.stringify(this.routes, null, 2);
-      await this.storageManager.set('/email/routes/config.tson', routesData);
+      await this.storageManager.set('/email/routes/config.json', routesData);
       
       this.emit('routesPersisted', this.routes.length);
     } catch (error) {
@@ -430,7 +431,7 @@ export class EmailRouter extends plugins.EventEmitter {
     }
     
     try {
-      const routesData = await this.storageManager.get('/email/routes/config.tson');
+      const routesData = await this.storageManager.get('/email/routes/config.json');
       
       if (!routesData) {
         return [];