refactor: organize desktop vs. mobile into separate folders

js/desktop/src/hooks/use-billing.ts

@@ -0,0 +1,29 @@
+import { useQuery, useMutation } from "@tanstack/react-query";
+import { apiClient } from "@/api/client";
+import type { BillingCadence } from "@/api/types";
+
+export function useNetworkBilling(networkId: string | undefined) {
+  return useQuery({
+    queryKey: ["network-billing", networkId],
+    queryFn: () => apiClient.getNetworkBilling(networkId!),
+    enabled: !!networkId,
+    // Refetch on window focus so the UI catches up after the user returns
+    // from Stripe Checkout (webhook may land a second or two later).
+    // FIX: doesn't work with electron
+    refetchOnWindowFocus: true,
+    refetchInterval: 10000
+  });
+}
+
+export function useCreateCheckoutSession(networkId: string) {
+  return useMutation({
+    mutationFn: (cadence: BillingCadence) =>
+      apiClient.createCheckoutSession(networkId, cadence),
+  });
+}
+
+export function useCreatePortalSession(networkId: string) {
+  return useMutation({
+    mutationFn: () => apiClient.createPortalSession(networkId),
+  });
+}