feat(jwt): handle nil keyset

pkg/module/auth/jwt.go

@@ -61,6 +61,10 @@ func FindToken(r *http.Request, getKeySet GetKeySetFunc) (jwt.Token, error) {
 		return nil, errors.WithStack(err)
 	}
 
+	if keySet == nil {
+		return nil, errors.New("no keyset")
+	}
+
 	token, err := jwt.Parse([]byte(rawToken),
 		jwt.WithKeySet(keySet, jws.WithRequireKid(false)),
 		jwt.WithValidate(true),