Twenty requires existing accounts to be members for SSO sign-in

Twenty v2.58.2 changes how SSO sign-in treats existing accounts. The SsoAuthController now requires an existing account to already be a member before sign-in completes.

The release also adds integration tests for SAML and OIDC sign-in. The SAML test posts a signed SAML response to POST /auth/saml/callback/:id. The OIDC test drives the login and callback routes against a local issuer. CI runs the OIDC suite only when SSO_TEST_* variables are set.

The release notes list this as a behavior change for existing Twenty accounts that are not yet members. The excerpt cuts off before it says what happens to those accounts.