zone.stratos.space.getSpaceCredential

Issue a space credential (JWT) for a space the caller is a member of. The credential is multi-use until it expires and is bound to the caller's DPoP key (cnf.jkt, RFC 9449): it must be presented under the DPoP auth scheme with a per-request proof signed by that key. It is signed by the space authority's signing key so any repo host can verify it without contacting the authority. Identity is resolved from a delegation token when provided (a standalone DPoP proof in the DPoP header supplies the key to bind), otherwise from the DPoP-authenticated user (the session proof key is bound). Membership is checked live against the enrollment store. App-axis (client attestation) gating is enforced here: spaces configured with an app allow-list require a valid client attestation whose attested client_id is listed; spaces that are open ignore any attestation supplied.