fix(pluto): restore SD+JWT credentials using SDJWTCredential
SD+JWT credentials were incorrectly deserialized as JWTCredential during backup restore. This caused selective disclosure data (disclosures) to be lost, making restored SD+JWT credentials unusable for presentations. The fix uses SDJWTCredential.fromJWS() for the 'sdjwt' recovery_id instead of JWTCredential.fromJWS(), preserving the full SD-JWT structure including disclosures. Closes #458