Frontend live dashboard doesn't fetch data from backend

[SL-Mar]

Problem

Frontend pages for live monitoring (app/live-dashboard/page.tsx, app/live/page.tsx) exist but don't connect to the backend API or WebSocket endpoints. The pages render UI shells without real data.

Steps to fix

1. Add API client methods in frontend/lib/api.ts for live endpoints
2. Implement WebSocket client for /api/live/ws
3. Connect weather grid data to WeatherGridLayer component
4. Add loading states and error handling
5. Add retry/reconnect logic for WebSocket

Files

• frontend/app/live/page.tsx
• frontend/app/live-dashboard/page.tsx
• frontend/lib/api.ts
• frontend/components/WeatherGridLayer.tsx