test(zoo-gateway): assert full cache survives empty model response

Strengthen the empty-response case to verify pre-existing providers (openrouter) are preserved, not just that zoo-gateway stays unset. Addresses CodeRabbit feedback on PR #490.

Author: JamesRobert20

webview-ui/src/components/ui/hooks/__tests__/useZooGatewayRouterModelsSync.spec.ts

@@ -110,6 +110,8 @@ describe("useZooGatewayRouterModelsSync", () => {
 		await waitFor(() => expect(mockFetchRouterModels).toHaveBeenCalled())
 		const cached = queryClient.getQueryData<RouterModels>(["routerModels", "all"])
 		expect(cached?.["zoo-gateway"]).toBeUndefined()
+		// The whole cache must survive an empty result, not just the zoo-gateway key.
+		expect(cached?.openrouter).toEqual({ "openai/gpt-4": modelInfo })
 	})
 
 	it("swallows fetch errors", async () => {