Block integer local-part emails in emailIsBad

[Copilot]

emailIsBad previously filtered only by blocked domains, allowing addresses like 123@domain.com through. This update extends the check to also treat integer-only local parts as bad inputs.

• Email filtering logic

  • Added integer local-part detection in emailIsBad.
  • Preserved existing blocked-domain behavior.

• Coverage updates

  • Added/updated unit tests for integer local-part handling in:
    • emailIsBad
    • fakeSubscribe
    • subscribe

• Behavior example

  emailIsBad('123@example.com'); // true
  emailIsBad('user@example.com'); // false
  emailIsBad('test@mailinator.com'); // true

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Project	Deployment	Actions	Updated (UTC)
mikebifulco-com-bnbu	Ready	Preview, Comment	Jun 13, 2026 7:30pm

[Copilot]

Pull request overview

This pull request updates newsletter subscription anti-abuse logic by expanding emailIsBad to also flag emails whose local-part is integer-only, and extends unit test coverage to ensure fakeSubscribe/subscribe treat those addresses as “bad” inputs.

Changes:

• Extended emailIsBad to return true when the local-part is composed only of digits.
• Added unit test coverage for integer-only local parts in emailIsBad, fakeSubscribe, and subscribe.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/utils/resend.ts	Updates emailIsBad filtering logic to include integer-only local parts.
src/utils/resend.test.ts	Adds tests asserting integer-only local parts are treated as “bad” for filtering and subscription flows.

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