feat(rust): scaffold Rust workspace and fix TypeScript build errors

- Add @git.zone/tsrust with linux_amd64/linux_arm64 cross-compilation
- Scaffold Rust workspace with 5 crates: mailer-core, mailer-smtp, mailer-security, mailer-napi, mailer-bin
- Fix all TypeScript compilation errors for upgraded dependencies (smartfile v13, mailauth v4.13, smartproxy v23)
- Replace smartfile.fs/memory with @push.rocks/smartfs throughout codebase
- Fix .ts import extensions to .js for NodeNext module resolution
- Update DKIMSignOptions usage to match mailauth v4.13 API
- Add MTA error classes with permissive signatures for legacy SMTP client
- Replace removed DcRouter/StorageManager/deliverability imports with local interfaces

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

@@ -3,15 +3,15 @@
  * Factory function for client creation and dependency injection
  */
 
-import { SmtpClient } from './smtp-client.ts';
-import { ConnectionManager } from './connection-manager.ts';
-import { CommandHandler } from './command-handler.ts';
-import { AuthHandler } from './auth-handler.ts';
-import { TlsHandler } from './tls-handler.ts';
-import { SmtpErrorHandler } from './error-handler.ts';
-import type { ISmtpClientOptions } from './interfaces.ts';
-import { validateClientOptions } from './utils/validation.ts';
-import { DEFAULTS } from './constants.ts';
+import { SmtpClient } from './smtp-client.js';
+import { ConnectionManager } from './connection-manager.js';
+import { CommandHandler } from './command-handler.js';
+import { AuthHandler } from './auth-handler.js';
+import { TlsHandler } from './tls-handler.js';
+import { SmtpErrorHandler } from './error-handler.js';
+import type { ISmtpClientOptions } from './interfaces.js';
+import { validateClientOptions } from './utils/validation.js';
+import { DEFAULTS } from './constants.js';
 
 /**
  * Create a complete SMTP client with all components