Complete email router implementation and documentation

- Cleaned up interface definitions to only include implemented features
- Updated readme.md with comprehensive route-based configuration examples
- Added common email routing patterns and troubleshooting guide
- Removed legacy DomainRouter and IDomainRule interfaces
- Updated all imports and exports to use new EmailRouter system
- Verified build and core functionality tests pass

The match/action pattern implementation is now complete and production-ready.

ts/mail/delivery/classes.delivery.system.ts

@@ -10,7 +10,6 @@ import {
 } from '../../security/index.js';
 import { UnifiedDeliveryQueue, type IQueueItem } from './classes.delivery.queue.js';
 import type { Email } from '../core/classes.email.js';
-import type { IDomainRule } from '../routing/classes.email.config.js';
 import type { UnifiedEmailServer } from '../routing/classes.unified.email.server.js';
 import type { SmtpClient } from './smtpclient/smtp-client.js';
 
@@ -50,7 +49,7 @@ export interface IMultiModeDeliveryOptions {
   
   // Mode-specific handlers
   forwardHandler?: IDeliveryHandler;
-  mtaHandler?: IDeliveryHandler;
+  deliveryHandler?: IDeliveryHandler;
   processHandler?: IDeliveryHandler;
   
   // Rate limiting
@@ -136,7 +135,7 @@ export class MultiModeDeliverySystem extends EventEmitter {
       forwardHandler: options.forwardHandler || {
         deliver: this.handleForwardDelivery.bind(this)
       },
-      mtaHandler: options.mtaHandler || {
+      deliveryHandler: options.deliveryHandler || {
         deliver: this.handleMtaDelivery.bind(this)
       },
       processHandler: options.processHandler || {
@@ -313,7 +312,7 @@ export class MultiModeDeliverySystem extends EventEmitter {
           break;
           
         case 'mta':
-          result = await this.options.mtaHandler.deliver(item);
+          result = await this.options.deliveryHandler.deliver(item);
           break;
           
         case 'process':