feat: add monitor center module

Changes:
- Add monitor center page with KPI cards, charts and request logs
- Implement channel stats, failure analysis, model distribution visualization
- Support time range filtering (last 1/6/24 hours)
- Add model disable feature with related hooks and state management
- Optimize request logs list performance with virtual scrolling
- Improve mobile styles and table scrolling experience
- Add i18n support for Chinese and English

Modified files:
- src/pages/MonitorPage.tsx (added)
- src/components/monitor/* (added, 10 components)
- src/hooks/useDisableModel.ts (added)
- src/utils/monitor.ts (added)
- src/i18n/locales/*.json (modified)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

package.json

@@ -13,6 +13,7 @@
   },
   "dependencies": {
     "@codemirror/lang-yaml": "^6.1.2",
+    "@tanstack/react-virtual": "^3.13.18",
     "@uiw/react-codemirror": "^4.25.3",
     "axios": "^1.13.2",
     "chart.js": "^4.5.1",