Implement Credly OBI-compliant assertion endpoints so a third-party platform can verify Credly-issued badges via Open Badges protocol

Steps

1. Review the OBI Endpoints documentation at https://www.credly.com/docs/obi_specified_endpoints which describes the Open Badges Infrastructure endpoints Credly exposes
2. Access badge assertion JSON via GET https://api.credly.com/v1/obi/v2/assertions/{issued_badge_id}; this returns an OBI 2.0-compliant assertion object for legacy verifiers
3. Access the badge class (template definition) via GET https://api.credly.com/v1/obi/v2/badge_classes/{badge_template_id}; response includes name, description, image, and criteria fields
4. Access the issuer profile via GET https://api.credly.com/v1/obi/v2/issuers/{organization_id}; response includes the issuing organization's name, url, and email
5. For OB 3.0 verification, Credly returns a signed AchievementCredential JSON-LD document with a DataIntegrityProof; retrieve via the Credly badge sharing URL with format=json query parameter
6. Build a verification workflow: fetch the assertion, resolve the issuer DID from the issuer field, verify the cryptographic proof, and check the credentialStatus (if present) against the status list URL