fix preprocess to expand properties dict instead of add as a node to …

[ryanmco]

Avoid traversing properties with names that match json schema keywords.

Error occurs when processing common/types/constraint_expression.json

Generating Pydantic models from preprocessed schemas...
Error at schema path 'common/types/constraint_expression.json#': ValidationError: 2 validation errors for JsonSchemaObject
properties.anyOf.JsonSchemaObject
  Input should be a valid dictionary or instance of JsonSchemaObject [type=model_type, input_value=['type', 'description', 'minItems', 'items'], input_type=list]
    For further information visit https://errors.pydantic.dev/2.13/v/model_type
properties.anyOf.bool
  Input should be a valid boolean [type=bool_type, input_value=['type', 'description', 'minItems', 'items'], input_type=list]
    For further information visit https://errors.pydantic.dev/2.13/v/bool_type

This is fixed by instead adding the properties mapping itself (the container dictionary { "prop_name": { ...schema... } }), it immediately adds each property's inner schema dictionary (v.values()) directly to the traversal list.

Before vs After

{
  "type": "object",
  "properties": {
    "user_id": { "type": "string", "$ref": "#/$defs/id" },
    "properties": { "type": "object", ... }
  }
}

Before

1. Yields root object { "type": "object", "properties": { ... } }
2. Yields the container dictionary { "user_id": { ... }, "properties": { ... } } (which is just a key-value map of property names, not a schema definition itself)
3. Yields { "type": "string", "$ref": "#/$defs/id" }
4. Yields { "type": "object", .... }

After (with the fix):
Yields root object { "type": "object", "properties": { ... } }
Yields { "type": "string", "$ref": "#/$defs/id" } (container is skipped)
Yields { "type": "object", ... }

This prevents functions inspecting yielded nodes (like checking for anyOf, properties,...) from the container map itself as if it were a schema.

Description

Category (Required)

Please select one or more categories that apply to this change.

• Core Protocol: Changes to the base communication layer, global context, or breaking refactors. (Requires Technical Council approval)
• Governance/Contributing: Updates to GOVERNANCE.md, CONTRIBUTING.md, or CODEOWNERS. (Requires Governance Council approval)
• Capability: New schemas (Discovery, Cart, etc.) or extensions. (Requires Maintainer approval)
• Documentation: Updates to README, or documentations regarding schema or capabilities. (Requires Maintainer approval)
• Infrastructure: CI/CD, Linters, or build scripts. (Requires DevOps Maintainer approval)
• Maintenance: Version bumps, lockfile updates, or minor bug fixes. (Requires DevOps Maintainer approval)
• [ x] SDK: Language-specific SDK updates and releases. (Requires DevOps Maintainer approval)
• Samples / Conformance: Maintaining samples and the conformance suite. (Requires Maintainer approval)
• UCP Schema: Changes to the ucp-schema tool (resolver, linter, validator). (Requires Maintainer approval)
• Community Health (.github): Updates to templates, workflows, or org-level configs. (Requires DevOps Maintainer approval)

Related Issues

Checklist

• [ x] I have followed the Contributing Guide (including Conventional Commits title requirements and ! for breaking changes).
• I have updated the documentation (if applicable).
• [ x] My changes pass all local linting and formatting checks.
• [ x] I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• (For Core/Capability) I have included/updated the relevant JSON schemas.
• I have regenerated Python Pydantic models by running generate_models.sh under python_sdk.

Screenshots / Logs (if applicable)