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/useRuns.ts

@@ -0,0 +1,47 @@
+import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
+import { getRuns, getRun, createRun, updateRun, deleteRun } from '../api/runs'
+import type { CreateRunInput, UpdateRunInput } from '../types/game'
+
+export function useRuns() {
+  return useQuery({
+    queryKey: ['runs'],
+    queryFn: getRuns,
+  })
+}
+
+export function useRun(id: number) {
+  return useQuery({
+    queryKey: ['runs', id],
+    queryFn: () => getRun(id),
+  })
+}
+
+export function useCreateRun() {
+  const queryClient = useQueryClient()
+  return useMutation({
+    mutationFn: (data: CreateRunInput) => createRun(data),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['runs'] })
+    },
+  })
+}
+
+export function useUpdateRun(id: number) {
+  const queryClient = useQueryClient()
+  return useMutation({
+    mutationFn: (data: UpdateRunInput) => updateRun(id, data),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['runs'] })
+    },
+  })
+}
+
+export function useDeleteRun() {
+  const queryClient = useQueryClient()
+  return useMutation({
+    mutationFn: (id: number) => deleteRun(id),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['runs'] })
+    },
+  })
+}