CVE-2026-41164: nuts-node has JWT type confusion in v1 access token introspection that allows VP replay as access token

The v1 access token introspection endpoint (/auth/v1/introspect_access_token) accepts any JWT signed by a key present on the node, without validating the JWT type, issuer-to-key binding, or required claims. This allows a Verifiable Presentation (VP) JWT to be replayed as an access token and receive an active: true introspection response.