Support for RetryAfter

Inngest has a concept of throwing a RetryAfterError, which is most helpful when working with external services where we hit a rate limit and I just need to retry after a specific amount of time (once the rate limit resets). Can this be added to this component?

The issue names no files, tests, or entry points. Start by tracing how workflow errors and retry timing are represented, then determine how a RetryAfterError from a rate-limited external service should be handled. Done means the component supports the requested retry-after behavior with tests covering it.

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