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/api/games.ts

@@ -0,0 +1,22 @@
+import { api } from './client'
+import type { Game, Route, RouteEncounter } from '../types/game'
+
+export interface GameDetail extends Game {
+  routes: Route[]
+}
+
+export function getGames(): Promise<Game[]> {
+  return api.get('/games')
+}
+
+export function getGame(id: number): Promise<GameDetail> {
+  return api.get(`/games/${id}`)
+}
+
+export function getGameRoutes(gameId: number): Promise<Route[]> {
+  return api.get(`/games/${gameId}/routes`)
+}
+
+export function getRoutePokemon(routeId: number): Promise<RouteEncounter[]> {
+  return api.get(`/routes/${routeId}/pokemon`)
+}