Initial commit: accountbook project

- Node.js backend server
- Frontend application
- Backup script
- Project specification

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/package.json

@@ -0,0 +1,16 @@
+{
+  "name": "accountbook-frontend",
+  "version": "1.0.0",
+  "private": true,
+  "scripts": {
+    "dev": "next dev -p 3500",
+    "build": "next build",
+    "start": "next start -p 3500"
+  },
+  "dependencies": {
+    "chart.js": "^4.5.1",
+    "next": "^14.0.0",
+    "react": "^18.2.0",
+    "react-dom": "^18.2.0"
+  }
+}