Changes an existing tenantUser's role by calling the REAL tenantUserService.update() — which bumps tokenVersion and publishes `user.state_changed` on the per-user realtime channel. The SDK subscribed to that channel refreshes its tokens, so the new role propagates live (no page reload). Drives the realtime live-role-change Playwright test. POST /account/test/playwright/update-tenant-user-role Headers: x-playwright-api-key: <your-api-key> Body: { tenantUserId, tenantId, role: 'OWNER'|'ADMIN'|'MEMBER', appDomain? } Returns: { tenantUserId, role }