Sets up the admin app (NBLOCKS_DASHBOARD) with an owner user, properly linked. This is the RECOMMENDED endpoint for Playwright global setup. Combines: 1. App creation (if needed) 2. Owner/tenant creation (if needed) 3. linkApp() call to set critical metadata POST /account/test/playwright/setup-admin-app-with-owner Headers: x-playwright-api-key: <your-api-key> Body: { adminUiUrl: string, ownerEmail: string, ownerPassword?: string } Returns: { appId, domain, tenantId, userId, email, message }