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>

package.json

@@ -0,0 +1,23 @@
+{
+  "name": "kakeibo",
+  "private": true,
+  "description": "Kakeibo — Kişisel Ev Finans Defteri",
+  "scripts": {
+    "postinstall": "npm --prefix frontend install",
+    "predev": "npm run db:up",
+    "dev": "concurrently -k -n api,web -c blue,green \"npm:dev:api\" \"npm:dev:web\"",
+    "dev:api": "cd backend && cargo watch -q -c -x run",
+    "dev:web": "npm --prefix frontend run dev",
+    "predev:host": "npm run db:up",
+    "dev:host": "concurrently -k -n api,web -c blue,green \"npm:dev:api\" \"npm --prefix frontend run dev -- --host\"",
+    "db:up": "docker compose -f docker-compose.dev.yml up -d --wait",
+    "db:down": "docker compose -f docker-compose.dev.yml stop",
+    "db:seed": "echo 'Seed betiği Faz 1-4 arasında eklenecek.'",
+    "db:reset": "docker exec kakeibo-mongo mongosh --quiet kakeibo_dev --eval 'db.dropDatabase()' && echo 'kakeibo_dev veritabanı sıfırlandı.'",
+    "test": "cd backend && cargo test",
+    "lint": "cd backend && cargo clippy && cd .. && npm --prefix frontend run lint"
+  },
+  "devDependencies": {
+    "concurrently": "^10.0.7"
+  }
+}