Implement Da Vinci CRD Coverage Requirements Discovery via CDS Hooks order-sign and order-select hooks

Verified steps

1. Register CDS Hook services for 'order-select' (fires when a new order is selected before signing) and 'order-sign' (fires when the clinician finalizes an order) in your CDS service discovery endpoint at /.well-known/cds-services
2. Receive the CDS Hook request context: parse hook.context.draftOrders (a FHIR Bundle of proposed orders) and hook.prefetch for Patient, Coverage, and Encounter data pre-fetched by the EHR to avoid extra server calls
3. Query the payer's CRD service endpoint with the hook payload; the payer evaluates coverage requirements and returns CDS Cards with types: Information (coverage details), Warning (documentation needed), or Hard Stop (prior auth required)
4. For cards with type 'suggestion', inspect Card.suggestions[].actions for FHIR resource update actions that the EHR can apply — for example, adding a Coverage resource or updating the order with a required modifier
5. For cards indicating prior authorization required, surface a card with a SMART App Launch link to the DTR SMART app so the clinician can complete the documentation questionnaire inline
6. Return the CDS response within the latency requirement (typically under 5 seconds); for slow payer lookups, return a response with systemActions and handle out-of-band completion via the CDS Hooks feedback endpoint