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>

web/package.json

@@ -0,0 +1,27 @@
+{
+  "name": "x-agent-dashboard",
+  "private": true,
+  "version": "0.0.1",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "vue-tsc && vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "echarts": "^6.0.0",
+    "element-plus": "^2.13.3",
+    "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"
+  }
+}