feat: add Batch.SendParams with scheduled_at, tags, and attachments

[cpenned]

Summary

The batch send API now supports scheduled_at, tags, and attachments per email. This PR adds a dedicated Batch.SendParams type so those fields are explicitly documented and typed for batch sends.

Changes

• Add Batch.SendParams extending Emails.SendParams with batch-specific documentation for scheduled_at, tags, and attachments
• Update Batch.send / Batch.send_async signatures to accept List[Batch.SendParams]
• Document scheduled_at on Emails.SendParams (was present in the TypedDict but missing from docs)
• Add a test verifying tags, attachments, and scheduled_at are serialized in the batch request payload
• Update batch examples and tests to use Batch.SendParams

Notes

Runtime behavior is unchanged — the SDK already forwarded these fields when using Emails.SendParams. This makes the batch API surface explicit and discoverable.

  

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Summary by cubic

Adds a dedicated Batch.SendParams so per-email scheduled_at, tags, and attachments are clearly supported in batch sends. Updates the batch API to accept the new type; no runtime behavior change. Also resolves lint and mypy errors introduced by these changes.

• New Features

  • Added Batch.SendParams (extends Emails.SendParams) with explicit docs for scheduled_at, tags, and attachments; documented scheduled_at on Emails.SendParams.
  • Updated Batch.send/Batch.send_async to accept List[Batch.SendParams]; tests verify serialization; examples updated.

• Migration

  • Replace List[resend.Emails.SendParams] with List[resend.Batch.SendParams] when calling Batch.send or Batch.send_async.

^{Written for commit f97748d. Summary will update on new commits.}

[cubic-dev-ai]

0 issues found across 2 files (changes from recent commits).

<sub>Auto-approved: Adds a new TypedDict subclass, updates type annotations, and adds a test. No runtime logic changes, just explicit typing and documentation.

Re-trigger cubic</sub>