Latest dstack configuration JSON schema is invalid

[r4victor]

If I define a .dstack.yaml configuration, I see VSCode complaining about the parts of the JSON schema being invalid:

This bug was introduced when we migrated to pydantic-duality models (#967) because ResourcesSpec reference is hardcoded while it should be ResourcesSpecRequest after introducing pydantic-duality:

dstack/src/dstack/_internal/core/models/resources.py

Line 217 in c3687db

ref_template = "#/definitions/ResourcesSpec/definitions/{model}"

• Fix ResourcesSpec reference.
• Add tests to validate json schema.