Add frontend API client and TanStack Query hooks

Install @tanstack/react-query, create a fetch-based API client with typed
functions for all endpoints, and add query/mutation hooks for games, pokemon,
runs, and encounters. Includes Vite dev proxy for /api and QueryClientProvider
setup.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/hooks/useGames.ts

@@ -0,0 +1,31 @@
+import { useQuery } from '@tanstack/react-query'
+import { getGames, getGame, getGameRoutes, getRoutePokemon } from '../api/games'
+
+export function useGames() {
+  return useQuery({
+    queryKey: ['games'],
+    queryFn: getGames,
+  })
+}
+
+export function useGame(id: number) {
+  return useQuery({
+    queryKey: ['games', id],
+    queryFn: () => getGame(id),
+  })
+}
+
+export function useGameRoutes(gameId: number) {
+  return useQuery({
+    queryKey: ['games', gameId, 'routes'],
+    queryFn: () => getGameRoutes(gameId),
+  })
+}
+
+export function useRoutePokemon(routeId: number | null) {
+  return useQuery({
+    queryKey: ['routes', routeId, 'pokemon'],
+    queryFn: () => getRoutePokemon(routeId!),
+    enabled: routeId !== null,
+  })
+}