* test(ui-e2e): add admin key creation with a specific proxy model
Adds Playwright coverage for creating a key (no team) scoped to a single
proxy model, complementing the existing All-Proxy-Models test. Uses a
DOM-dispatched click on the antd dropdown option since the popup
animation can render the option outside the viewport.
* test(ui-e2e): verify scoped key works against mock /chat/completions
Extend the "Create a key with a specific proxy model" test to extract
the new key from the success modal and POST to /chat/completions for
the scoped model, asserting 200 and the mock response body. Without
this the test could pass even if the model selection failed to register.