feat(email-sdk): add Cloudflare Worker binding support to cloudflare adapter

[imorius]

Why

The Cloudflare adapter only supported Cloudflare's Email Sending REST API (apiToken and accountId). Applications running directly inside a Cloudflare Worker could not utilize the native SendEmail Worker binding (env.SEB), forcing unnecessary API token configuration.

What changed

• add Cloudflare Worker Email Sending Binding (SendEmail) support to the cloudflare() adapter
• allow passing binding option (e.g. binding: env.SEB) as a mutually exclusive alternative to REST API credentials (apiToken/accountId)
• map message recipients (to, cc, bcc, replyTo), headers, text/html content, and attachments to the Cloudflare Worker binding payload
• add unit tests for binding send behavior, result message ID parsing, and error handling in cloudflare.test.ts
• update Cloudflare adapter documentation in apps/fumadocs with Worker binding configuration examples and <TypeTable> options
• add a minor changeset for @opencoredev/email-sdk

[vercel]

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[greptile-apps]

Greptile Summary

The Cloudflare adapter now supports sending through a native Worker Email Sending binding as an alternative to REST credentials. Focused execution confirmed the binding path sends attachments in a supported format, preserves recipients, and normalizes returned message IDs. No blocking failure remains.

Confidence Score: 5/5

No blocking failure remains.

The Worker binding path and focused Cloudflare adapter tests completed successfully, with no accepted blocking findings.

T-Rex Logs

What T-Rex did

• Ran the baseline Cloudflare binding contract repro script and observed bindingCalls were 0 with an HTTP fallback.
• Ran the current Cloudflare binding contract repro script and observed bindingCalls 1, attachmentContent "AP9B", returnedId "cf-message-42", and accepted recipients to@example.com and cc@example.com.
• Ran the Cloudflare-related tests; all tests passed (8 pass, 0 fail).
• Fetched PR comments via the GitHub API and found no comments (empty array).

_{Ran code and verified through T-Rex}

_{Reviews (2): Last reviewed commit: "chore(docs): update lastmod timestamps" | Re-trigger Greptile}