fix(mail): migrate filesystem helpers to fsUtils, update DKIM and mail APIs, harden SMTP client, and bump dependencies

ts/mail/core/classes.bouncemanager.ts

@@ -650,7 +650,7 @@ export class BounceManager {
         await this.storageManager.set('/email/bounces/suppression-list.json', suppressionData);
       } else {
         // Fall back to filesystem
-        plugins.smartfile.memory.toFsSync(
+        plugins.fsUtils.toFsSync(
           suppressionData,
           plugins.path.join(paths.dataDir, 'emails', 'suppression_list.json')
         );
@@ -744,9 +744,9 @@ export class BounceManager {
         
         // Ensure directory exists
         const bounceDir = plugins.path.join(paths.dataDir, 'emails', 'bounces');
-        plugins.smartfile.fs.ensureDirSync(bounceDir);
+        plugins.fsUtils.ensureDirSync(bounceDir);
         
-        plugins.smartfile.memory.toFsSync(bounceData, bouncePath);
+        plugins.fsUtils.toFsSync(bounceData, bouncePath);
       }
     } catch (error) {
       logger.log('error', `Failed to save bounce record: ${error.message}`);