Return Structured JSON Errors with Reason as a key

[BornPsych]

zk-email-verify/packages/helpers/src/dkim/index.ts

Line 79 in 045a7da

throw new Error(`DKIM signature verification failed for domain ${signingDomain}. Reason: ${comment}`);

Currently, errors are returned as plain strings, which makes it harder to programmatically handle and segregate them in downstream applications.

throw new Error(JSON.stringify({
   message: `DKIM signature verification failed for domain ${signingDomain}.`,
  reason:  `${comment}`
}));