Let spawn_blocking handle returning its own value

[RealOrangeOne]

This means one fewer thing to await on, and spin up inside a request. It might be faster, who knows, but it can't hurt.

[sweep-ai]

Apply Sweep Rules to your PR?

• Apply: All new business logic should have corresponding unit tests.
• Apply: Refactor large functions to be more modular.
• Apply: Add docstrings to all functions and file headers.

[FireMasterK]

Thanks!