docs: Add standards document for adoption of new SDKs

[krishicks]

On the July 14, 2026 community call the issue of new SDK adoption came up. Presently we don't have any kind of standard for adopting new SDKs.

It would be good if we had a document which declared the standard that must be met before an SDK is adopted.

I think the standard should include:

• Local dev environment support. This may be obvious, but it means making sure mise or Nix or bazel or whichever tooling we use for specifying the environment incorporates support for the SDK's language
• linting and unit testing of the SDK
• hooking that linting and unit testing into the automated testing mechanism (presently mise)
• Adding that to CI, probably as its own task/action
• Documenting the available features of the SDK. During development the SDK may not support everything, but even after release there may be some inherent limitations of the SDK, or new features of OpenShell not yet supported by it, so those should be documented. I have in mind how Gateway API does it.

It would be extremely valuable if we had a conformance testing environment that we could run SDK tests against; a predefined set of actions that the SDK will exercise to show it conforms to some level of OpenShell support. We don't have that yet, but if we did have that, the standard would include running that conformance test.