feat(api): add team RBAC and complete sync and async email options

[bjarn]

Summary

• Add the current team role and member assignment API.
• Update generated delivery models.
• Add per-email TLS and tracking settings.
• Add attachment MIME types and typed batch payloads.
• Send batch idempotency keys in the synchronous and asynchronous clients.
• Test Message-ID preservation headers.

The generated types included the new fields, but the fluent sending endpoints and batch annotations were incomplete.

Checks

• ruff check .
• mypy src
• pytest — 60 tests passed