feat(altyapı): yerel MongoDB, Axum backend ve Vite frontend iskeleti

- docker-compose.dev.yml: MongoDB 7, tek düğümlü replica set (port 27020)
- Backend: Axum + tokio, GET /api/health
- Frontend: React + TypeScript + Vite, /api proxy, geçici durum ekranı
- Kök package.json: npm run dev ile DB + backend + frontend
- backend/api.http örnek istekler

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

frontend/index.html

@@ -0,0 +1,13 @@
+<!doctype html>
+<html lang="tr">
+  <head>
+    <meta charset="UTF-8" />
+    
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Kakeibo</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/main.tsx"></script>
+  </body>
+</html>