feat: add admin UI frontend and complete backend APIs

- Add Vue 3 frontend with Element Plus
- Implement login, dashboard, tenant management
- Add app configuration, logs viewer, stats pages
- Add user management for admins
- Update Drone CI to build and deploy frontend
- Frontend ports: 3001 (test), 4001 (prod)

frontend/package.json

@@ -0,0 +1,26 @@
+{
+  "name": "000-platform-admin",
+  "version": "1.0.0",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "vue": "^3.4.0",
+    "vue-router": "^4.2.0",
+    "pinia": "^2.1.0",
+    "axios": "^1.6.0",
+    "element-plus": "^2.5.0",
+    "@element-plus/icons-vue": "^2.3.0",
+    "echarts": "^5.4.0",
+    "dayjs": "^1.11.0"
+  },
+  "devDependencies": {
+    "@vitejs/plugin-vue": "^5.0.0",
+    "vite": "^5.0.0",
+    "sass": "^1.69.0"
+  }
+}