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

ts/mail/delivery/classes.emailsignjob.ts

@@ -28,38 +28,12 @@ export class EmailSignJob {
 
   public async getSignatureHeader(emailMessage: string): Promise<string> {
     const signResult = await plugins.dkimSign(emailMessage, {
-      // Optional, default canonicalization, default is "relaxed/relaxed"
-      canonicalization: 'relaxed/relaxed', // c=
-
-      // Optional, default signing and hashing algorithm
-      // Mostly useful when you want to use rsa-sha1, otherwise no need to set
+      signingDomain: this.jobOptions.domain,
+      selector: this.jobOptions.selector,
+      privateKey: await this.loadPrivateKey(),
+      canonicalization: 'relaxed/relaxed',
       algorithm: 'rsa-sha256',
-
-      // Optional, default is current time
-      signTime: new Date(), // t=
-
-      // Keys for one or more signatures
-      // Different signatures can use different algorithms (mostly useful when
-      // you want to sign a message both with RSA and Ed25519)
-      signatureData: [
-        {
-          signingDomain: this.jobOptions.domain, // d=
-          selector: this.jobOptions.selector, // s=
-          // supported key types: RSA, Ed25519
-          privateKey: await this.loadPrivateKey(), // k=
-
-          // Optional algorithm, default is derived from the key.
-          // Overrides whatever was set in parent object
-          algorithm: 'rsa-sha256',
-
-          // Optional signature specifc canonicalization, overrides whatever was set in parent object
-          canonicalization: 'relaxed/relaxed', // c=
-
-          // Maximum number of canonicalized body bytes to sign (eg. the "l=" tag).
-          // Do not use though. This is available only for compatibility testing.
-          // maxBodyLength: 12345
-        },
-      ],
+      signTime: new Date(),
     });
     const signature = signResult.signatures;
     return signature;