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/smtpserver/secure-server.ts

@@ -3,14 +3,14 @@
  * Provides helper functions for creating and managing secure TLS server
  */
 
-import * as plugins from '../../../plugins.ts';
+import * as plugins from '../../../plugins.js';
 import { 
   loadCertificatesFromString, 
   generateSelfSignedCertificates,
   createTlsOptions,
   type ICertificateData
-} from './certificate-utils.ts';
-import { SmtpLogger } from './utils/logging.ts';
+} from './certificate-utils.js';
+import { SmtpLogger } from './utils/logging.js';
 
 /**
  * Create a secure TLS server for direct TLS connections