feat(26-02): React Query hooks for discovery data

- Create useDiscoverySetups, useDiscoveryItems, useDiscoveryCategories hooks
- Export DiscoverySetup and DiscoveryCategory interfaces
- Set staleTime 2min for setups/items, 5min for categories

src/client/hooks/useDiscovery.ts

@@ -0,0 +1,65 @@
+import { useQuery } from "@tanstack/react-query";
+import { apiGet } from "../lib/api";
+
+export interface DiscoverySetup {
+	id: number;
+	name: string;
+	createdAt: string;
+	itemCount: number;
+	creatorName: string | null;
+}
+
+export interface DiscoveryCategory {
+	name: string;
+	itemCount: number;
+}
+
+interface GlobalItem {
+	id: number;
+	brand: string;
+	model: string;
+	category: string | null;
+	weightGrams: number | null;
+	priceCents: number | null;
+	imageUrl: string | null;
+	description: string | null;
+	sourceUrl: string | null;
+	imageCredit: string | null;
+	imageSourceUrl: string | null;
+	createdAt: string;
+}
+
+interface CursorPage<T> {
+	items: T[];
+	nextCursor: string | null;
+	hasMore: boolean;
+}
+
+export function useDiscoverySetups(limit = 6) {
+	return useQuery({
+		queryKey: ["discovery", "setups", limit],
+		queryFn: () =>
+			apiGet<CursorPage<DiscoverySetup>>(
+				`/api/discovery/setups?limit=${limit}`,
+			),
+		staleTime: 2 * 60 * 1000,
+	});
+}
+
+export function useDiscoveryItems(limit = 8) {
+	return useQuery({
+		queryKey: ["discovery", "items", limit],
+		queryFn: () =>
+			apiGet<CursorPage<GlobalItem>>(`/api/discovery/items?limit=${limit}`),
+		staleTime: 2 * 60 * 1000,
+	});
+}
+
+export function useDiscoveryCategories(limit = 12) {
+	return useQuery({
+		queryKey: ["discovery", "categories", limit],
+		queryFn: () =>
+			apiGet<DiscoveryCategory[]>(`/api/discovery/categories?limit=${limit}`),
+		staleTime: 5 * 60 * 1000,
+	});
+}