fix: prevent silent attachment loss on email forwarding

[neilhtennek]

Problem

When getAttachmentContent() fails to retrieve an attachment (missing raw email data, malformed MIME, parser error), the forwarder logs a warning and calls continue — silently skipping the attachment. The email still forwards and gets marked as delivered. The success log even reports the original attachment count, not the actual number included.

This means a user can receive a forwarded email that is missing attachments with no indication that anything went wrong. Silent data loss.

Fix

Replace the continue with a throw so the forwarding operation fails visibly when an attachment cannot be retrieved. The existing error handling in the caller (email-router.ts) already catches this, marks the email as failed, and logs the error — so the failure surfaces properly instead of being swallowed.

Before

if (!attachmentContent) {
  console.warn(`Could not retrieve content for attachment`)
  continue  // email sends without the attachment, marked as delivered
}

After

if (!attachmentContent) {
  throw new Error(`Failed to retrieve content for attachment. Aborting forward to prevent silent data loss.`)
}

One line change. No new dependencies.

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@neilhtennek | @PreviewOps

[vercel]

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[neilhtennek]

@R44VC0RP