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/index.ts

@@ -4,21 +4,21 @@
  */
 
 // Main client class and factory
-export * from './smtp-client.ts';
-export * from './create-client.ts';
+export * from './smtp-client.js';
+export * from './create-client.js';
 
 // Core handlers
-export * from './connection-manager.ts';
-export * from './command-handler.ts';
-export * from './auth-handler.ts';
-export * from './tls-handler.ts';
-export * from './error-handler.ts';
+export * from './connection-manager.js';
+export * from './command-handler.js';
+export * from './auth-handler.js';
+export * from './tls-handler.js';
+export * from './error-handler.js';
 
 // Interfaces and types
-export * from './interfaces.ts';
-export * from './constants.ts';
+export * from './interfaces.js';
+export * from './constants.js';
 
 // Utilities
-export * from './utils/validation.ts';
-export * from './utils/logging.ts';
-export * from './utils/helpers.ts';
+export * from './utils/validation.js';
+export * from './utils/logging.js';
+export * from './utils/helpers.js';