Redirect Flow
User clicks login on partner site → partner validates username/password.
Partner backend calls init-auth → gets verifyPath.
Partner redirects user to WallNet-Sec: 302 → /verify/:sessionToken.
User solves visual challenge on WallNet-Sec hosted page.
WallNet-Sec redirects back to callbackUrl with result + signature + state.
Partner backend calls consume-result to validate → creates session on PASS.