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/package-lock.json

@@ -8,6 +8,7 @@
       "name": "frontend",
       "version": "0.0.0",
       "dependencies": {
+        "@tanstack/react-query": "^5.90.20",
         "react": "^19.2.0",
         "react-dom": "^19.2.0",
         "react-router-dom": "^7.13.0"
@@ -1644,6 +1645,32 @@
         "vite": "^5.2.0 || ^6 || ^7"
       }
     },
+    "node_modules/@tanstack/query-core": {
+      "version": "5.90.20",
+      "resolved": "https://registry.npmjs.org/@tanstack/query-core/-/query-core-5.90.20.tgz",
+      "integrity": "sha512-OMD2HLpNouXEfZJWcKeVKUgQ5n+n3A2JFmBaScpNDUqSrQSjiveC7dKMe53uJUg1nDG16ttFPz2xfilz6i2uVg==",
+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/tannerlinsley"
+      }
+    },
+    "node_modules/@tanstack/react-query": {
+      "version": "5.90.20",
+      "resolved": "https://registry.npmjs.org/@tanstack/react-query/-/react-query-5.90.20.tgz",
+      "integrity": "sha512-vXBxa+qeyveVO7OA0jX1z+DeyCA4JKnThKv411jd5SORpBKgkcVnYKCiBgECvADvniBX7tobwBmg01qq9JmMJw==",
+      "license": "MIT",
+      "dependencies": {
+        "@tanstack/query-core": "5.90.20"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/tannerlinsley"
+      },
+      "peerDependencies": {
+        "react": "^18 || ^19"
+      }
+    },
     "node_modules/@types/babel__core": {
       "version": "7.20.5",
       "resolved": "https://registry.npmjs.org/@types/babel__core/-/babel__core-7.20.5.tgz",