DCQL: mandatory + optional groups (student transport pass)

Scenario

A transport authority sells a discounted student pass. Mandatory: PID (identity) AND student status (Student ID card OR Enrolment Letter). Optional (required: false): local-residency proof (Utility Bill OR Rental Agreement) for an additional discount - the wallet presents it only if the holder has and consents to it.

Prerequisites

• An iGrant.io Organisation Wallet Suite (OWS) API key. Get it from support@igrant.io. Keep it on the server, in an environment variable or a secret manager. The browser never sees it.
• The OWS environment the key belongs to. The default is demo (https://demo-api.igrant.io). Use staging (https://staging-api.igrant.io) only when the integrator asks for it. A key works only in its own environment.