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/delivery/smtpclient/command-handler.ts

@@ -3,7 +3,7 @@
  * SMTP command sending and response parsing
  */
 
-import * as plugins from '../../../plugins.ts';
+import { EventEmitter } from 'node:events';
 import { SMTP_COMMANDS, SMTP_CODES, LINE_ENDINGS } from './constants.ts';
 import type { 
   ISmtpConnection, 
@@ -19,7 +19,7 @@ import {
 } from './utils/helpers.ts';
 import { logCommand, logDebug } from './utils/logging.ts';
 
-export class CommandHandler extends plugins.EventEmitter {
+export class CommandHandler extends EventEmitter {
   private options: ISmtpClientOptions;
   private responseBuffer: string = '';
   private pendingCommand: { resolve: Function; reject: Function; command: string } | null = null;

ts/mail/delivery/smtpclient/connection-manager.ts

@@ -3,18 +3,20 @@
  * Connection pooling and lifecycle management
  */
 
-import * as plugins from '../../../plugins.ts';
+import * as net from 'node:net';
+import * as tls from 'node:tls';
+import { EventEmitter } from 'node:events';
 import { DEFAULTS, CONNECTION_STATES } from './constants.ts';
-import type {
-  ISmtpClientOptions,
-  ISmtpConnection,
+import type { 
+  ISmtpClientOptions, 
+  ISmtpConnection, 
   IConnectionPoolStatus,
-  ConnectionState
+  ConnectionState 
 } from './interfaces.ts';
 import { logConnection, logDebug } from './utils/logging.ts';
 import { generateConnectionId } from './utils/helpers.ts';
 
-export class ConnectionManager extends plugins.EventEmitter {
+export class ConnectionManager extends EventEmitter {
   private options: ISmtpClientOptions;
   private connections: Map<string, ISmtpConnection> = new Map();
   private pendingConnections: Set<string> = new Set();

ts/mail/delivery/smtpclient/smtp-client.ts

@@ -3,7 +3,7 @@
  * Main client class with delegation to handlers
  */
 
-import * as plugins from '../../../plugins.ts';
+import { EventEmitter } from 'node:events';
 import type { Email } from '../../core/classes.email.ts';
 import type { 
   ISmtpClientOptions,
@@ -30,7 +30,7 @@ interface ISmtpClientDependencies {
   errorHandler: SmtpErrorHandler;
 }
 
-export class SmtpClient extends plugins.EventEmitter {
+export class SmtpClient extends EventEmitter {
   private options: ISmtpClientOptions;
   private connectionManager: ConnectionManager;
   private commandHandler: CommandHandler;