[Change Request] - Add fields to the Shared Type

Description

Context

The triage score and snapshot fields now live on the change request in the database, but the frontend won't receive them until they're included in the query and mapped through the transformer into the shared ChangeRequest type. This ticket makes the API actually return them.

Task

Add the new fields to the change-request shared type, the transformer, and (if needed) the query-args, so API responses include them.

Acceptance Criteria

• The shared ChangeRequest type includes triageScore (and the snapshot fields if the frontend will show them).
• The change-request transformer maps the new DB fields onto the returned object.
• Fetching a change request from the API returns triageScore populated for CRs that have one.