Add Database page with new connection feature

- Reorganize project structure: move frontend to web/ directory
- Add Database page with connection list (name, type, subtables, status, created, actions)
- Integrate Element Plus for UI components with dark theme support
- Add Quicksand font for rounded UI design
- Configure root package.json to run frontend from web/ directory

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

package.json

@@ -1,26 +1,11 @@
 {
-  "name": "x-agent-dashboard",
+  "name": "x-agents",
   "private": true,
   "version": "0.0.1",
-  "type": "module",
   "scripts": {
-    "dev": "vite",
-    "build": "vue-tsc && vite build",
-    "preview": "vite preview"
-  },
-  "dependencies": {
-    "echarts": "^6.0.0",
-    "pinia": "^2.1.7",
-    "vue": "^3.4.21",
-    "vue-router": "^4.3.0"
-  },
-  "devDependencies": {
-    "@vitejs/plugin-vue": "^5.0.4",
-    "autoprefixer": "^10.4.19",
-    "postcss": "^8.4.38",
-    "tailwindcss": "^3.4.3",
-    "typescript": "^5.4.3",
-    "vite": "^5.2.8",
-    "vue-tsc": "^2.0.7"
+    "dev": "cd web && npm run dev",
+    "build": "cd web && npm run build",
+    "preview": "cd web && npm run preview",
+    "install:web": "cd web && npm install"
   }
 }