feat: add OrderStatusCode values to reflect failure modes for orders

[nic-planet]

What I'm changing

• Adding FAILED and EXPIRED OrderStatusCodes
  We may get away with grouping those two failure modes into a single code, but I think we should have one.

Checklist

• [X ] Tests pass: uv run pytest

• Checks pass: uv run pre-commit --all-files
  FYI: pre-commit: error: unrecognized arguments: --all-files

• CHANGELOG is updated (if necessary)

[gadomski]

Since stapi-pydantic should function as a reference implementation for the spec itself, I think we should either:

• Add these statuses to the spec, e.g. in https://github.com/stapi-spec/stapi-spec/blob/main/order/README.md#order-status
• Use the existing statuses

I do see this text in that page:

Providers may support additional statuses through extensions. For example:

So we do need to update OrderStatusCode to allow custom statuses.

[nic-planet]

Since stapi-pydantic should function as a reference implementation for the spec itself, I think we should either:

• Add these statuses to the spec, e.g. in https://github.com/stapi-spec/stapi-spec/blob/main/order/README.md#order-status
• Use the existing statuses

I do see this text in that page:

Providers may support additional statuses through extensions. For example:

So we do need to update OrderStatusCode to allow custom statuses.

Oh you're right, I'm requesting that change here when actually I wanted to request it changed in the spec. Thanks for the custom statuses issue; I've also opened stapi-spec/stapi-spec#261 requesting that we have at least one status to represent a failed state.

[gadomski]

Sounds good! Marking as draft until it lands in the spec so we can align with whatever is decided there.