Publish OpenAPI spec for `sandboxd`

[knksmith57]

Per the v0.29.0-rc1 Release notes:

This release introduces a major new sandboxd HTTP API with an OpenAPI spec and fully generated client code
...

• Add OpenAPI spec and generated code for new sandboxd API (#2480)

This is wonderful and exciting! 🚀 ... Where can we find it?

[robmry]

Ah, those RC release notes might have over-stated things a bit!

It's very much work-in-progress, a start on some internal refactoring. So the API likely to evolve quite quickly in the short term, and may even turn into a ConnectRPC interface ... there's no plan to publish it at the moment, but it's not ruled out either.

But it is very interesting that you're interested! What sort of thing do you have in mind? (This is a good time to find out about requirements!)

[knksmith57]

there's no plan to publish it at the moment, but it's not ruled out either.

Very much appreciate the clarification and openness to potentially change/revisit that decision 🙏

What sort of thing do you have in mind? (This is a good time to find out about requirements!)

tl;dr: like any integrator, I'd much much rather our integration surface was a well-defined programmatic API, rather than a collection of sbx CLI subprocess execs and stdio serde.

I'm grateful for the inclusion of JSON output formatting support (it's a notable improvement over parsing porcelain); however, I'm sure we could both name an endless number of benefits to cutting out the messy middle and talking directly to the UDS.