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/security/classes.ipreputationchecker.ts

@@ -1,7 +1,7 @@
-import * as plugins from '../plugins.ts';
-import * as paths from '../paths.ts';
-import { logger } from '../logger.ts';
-import { SecurityLogger, SecurityLogLevel, SecurityEventType } from './classes.securitylogger.ts';
+import * as plugins from '../plugins.js';
+import * as paths from '../paths.js';
+import { logger } from '../logger.js';
+import { SecurityLogger, SecurityLogLevel, SecurityEventType } from './classes.securitylogger.js';
 import { LRUCache } from 'lru-cache';
 
 /**
@@ -472,10 +472,10 @@ export class IPReputationChecker {
       } else {
         // Fall back to filesystem
         const cacheDir = plugins.path.join(paths.dataDir, 'security');
-        plugins.smartfile.fs.ensureDirSync(cacheDir);
-        
+        await plugins.smartfs.directory(cacheDir).recursive().create();
+
         const cacheFile = plugins.path.join(cacheDir, 'ip_reputation_cache.json');
-        plugins.smartfile.memory.toFsSync(cacheData, cacheFile);
+        await plugins.smartfs.file(cacheFile).write(cacheData);
         
         logger.log('info', `Saved ${entries.length} IP reputation cache entries to disk`);
       }