ai-integrations: add AIResource spec.scope schema extension

[johnmcollier]

Summary

Add RHDH spec.scope support for AIResource entities in the ai-integrations workspace.

This issue covers the schema/model extension, validation behavior, and tests for spec.scope. It should stay focused on the spec.scope field itself and not expand into OCI processor work, entity-page work, or broader discovery work.

Tasks

• Extend or wrap the AIResource schema to support optional spec.scope
• Restrict valid spec.scope values to organization, product, and team
• Add actionable validation errors for invalid spec.scope values
• Ensure omitted spec.scope remains valid
• Add focused tests for valid, invalid, and omitted spec.scope cases

Acceptance Criteria

• spec.scope is supported as an optional RHDH extension on AIResource
• Valid values are exactly organization, product, and team
• Invalid values are rejected with an actionable validation error that identifies the field, received value, and accepted values
• Omitting spec.scope remains valid
• Tests cover valid, invalid, and omitted spec.scope behavior

Specifications

All paths below are relative to workspaces/ai-integrations/.

• openspec/changes/ai-resource-catalog-entity-kind/design.md
• openspec/changes/ai-resource-catalog-entity-kind/tasks.md (Section 1: Upstream Investigation & Schema Foundation)
• openspec/changes/ai-resource-catalog-entity-kind/specs/ai-resource-entity-schema/spec.md

Out of Scope

• OCI processor implementation
• oci:// target validation beyond any shared schema plumbing already required for spec.scope
• AIResource entity page rendering
• Discovery, filtering, and search support
• Example catalog-info.yaml files and broader documentation follow-up

Context

This issue covers the spec.scope portion of the RHDH AIResource extension model.

Keep the implementation focused on the schema/model extension and validation behavior for spec.scope only.

[johnmcollier]

/fs-triage