Validates a list of openapi route.

This function performs compile-time validation of a list of openapi route

Validation steps

1. Handler validation

   • If a global_handler is provided, it is validated to ensure it is a valid module.
   • Each route is checked to ensure its handler (or fallback global handler) is a valid module when required.

2. Operation ID validation

   • Ensures every route has a valid operationId.
   • Verifies that the resolved handler module exports a function matching the normalized operation id with arity 2 (operation_id(conn, params)).