feat(arayüz): API istemcisi, TanStack Query, ts-rs tip üretimi ve oturum durumu

- Backend: ts-rs ile DTO'lardan TypeScript tipleri (frontend/src/types, npm run types)
- Hata ve health yanıtları tipli yapılara çevrildi
- lib/api.ts: tek API istemcisi, Türkçe ApiError, ağ hatası mesajı
- lib/query.ts: QueryClient (4xx tekrar denenmez, 401 → oturum kapanır)
- lib/auth.ts: useMe, useLogin, useRegister, useLogout
- Vitest: 7 API istemcisi testi (toplam 29)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/package-lock.json

@@ -10,6 +10,7 @@
       "dependencies": {
         "@fontsource-variable/inter": "^5.3.0",
         "@tailwindcss/vite": "^4.3.5",
+        "@tanstack/react-query": "^5.107.1",
         "class-variance-authority": "^0.7.1",
         "cn": "^0.5.2",
         "lucide-react": "^1.72.0",
@@ -3356,6 +3357,38 @@
         "vite": "^5.2.0 || ^6 || ^7 || ^8"
       }
     },
+    "node_modules/@tanstack/query-core": {
+      "version": "5.107.1",
+      "resolved": "https://registry.npmjs.org/@tanstack/query-core/-/query-core-5.107.1.tgz",
+      "integrity": "sha512-PSyAik11oQBEVOiVy5hjZWHmoUqOXqK1WYy4v55mcxozEfKaQgpUMsgnXhWjuESzSht8JfzqMS1m6M/9CpNgvg==",
+      "license": "MIT",
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/tannerlinsley"
+      }
+    },
+    "node_modules/@tanstack/react-query": {
+      "version": "5.107.1",
+      "resolved": "https://registry.npmjs.org/@tanstack/react-query/-/react-query-5.107.1.tgz",
+      "integrity": "sha512-udCOOLp3ZAheUrIHLCe+ZZge6nr2ZUrGMSWcCuXsjY1Bf2JeeE09oxst97PILiCY6N8xo/7bIo3Hvz13zh06FA==",
+      "license": "MIT",
+      "dependencies": {
+        "@tanstack/query-core": "5.107.1"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/tannerlinsley"
+      },
+      "peerDependencies": {
+        "@types/react": "^18 || ^19",
+        "react": "^18 || ^19"
+      },
+      "peerDependenciesMeta": {
+        "@types/react": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/@ts-morph/common": {
       "version": "0.27.0",
       "resolved": "https://registry.npmjs.org/@ts-morph/common/-/common-0.27.0.tgz",