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/security/classes.dkimcreator.ts

@@ -1,7 +1,7 @@
-import * as plugins from '../../plugins.ts';
-import * as paths from '../../paths.ts';
+import * as plugins from '../../plugins.js';
+import * as paths from '../../paths.js';
 
-import { Email } from '../core/classes.email.ts';
+import { Email } from '../core/classes.email.js';
 // MtaService reference removed
 
 const readFile = plugins.util.promisify(plugins.fs.readFile);
@@ -46,8 +46,8 @@ export class DKIMCreator {
       console.log(`No DKIM keys found for ${domainArg}. Generating...`);
       await this.createAndStoreDKIMKeys(domainArg);
       const dnsValue = await this.getDNSRecordForDomain(domainArg);
-      plugins.smartfile.fs.ensureDirSync(paths.dnsRecordsDir);
-      plugins.smartfile.memory.toFsSync(JSON.stringify(dnsValue, null, 2), plugins.path.join(paths.dnsRecordsDir, `${domainArg}.dkimrecord.json`));
+      await plugins.smartfs.directory(paths.dnsRecordsDir).recursive().create();
+      await plugins.smartfs.file(plugins.path.join(paths.dnsRecordsDir, `${domainArg}.dkimrecord.json`)).write(JSON.stringify(dnsValue, null, 2));
     }
   }