feat: add idempotencyKey support to emails.receiving.forward()

[felipefreitag]

Accept a second request options argument, matching emails.send/create, and pass it to the internal POST /emails call so forwarded emails can be safely retried without duplicates.

Closes #967

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Summary by cubic

Adds optional request options to emails.receiving.forward() with idempotencyKey support, so forwards can be retried without duplicates. Aligns the method with emails.send/emails.create and closes #967.

• New Features
  • Adds a second argument requestOptions (ForwardReceivingEmailRequestOptions) with idempotencyKey and other PostOptions.
  • Applies options only to the internal POST /emails in both passthrough and wrapped modes; Idempotency-Key is not sent on the initial GET. Tests cover both cases.

^{Written for commit 93d1f8d. Summary will update on new commits.}

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/resend@997

commit: 93d1f8d

[cubic-dev-ai]

No issues found across 3 files

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

_{Re-trigger cubic}