Execute a single brick against a transport draft. Mirrors the operator-UI 'Test brick' button.

Logs. Each invocation persists log events to the brick's test-run log group (/test/productBricks/{brickId}). The synchronous response body also returns the brick's evaluation result.

Body shape. Discriminated by type:

• context — only transportDraftId (and optional productId) needed.
• feasibility / pricing / scheduling — additionally requires contextBrickId, the id of the context brick whose output is fed into this brick.