refactor(config): use APP_TARGET constant for backend URL configuration
Centralize backend URL configuration by introducing APP_TARGET constant in vite.config.js and using it for both WebSocket connection and API proxy. This improves maintainability by having a single source of truth for the backend address.
- Change API endpoint from POST to GET for instance status
- Update proxy target URL in vite config
- Add instance name display and remove initSystem from detail view
- Improve instance data handling in InstanceDetail component
- Update Home.vue to use flex layout and proper scrolling
- Enhance Logs.vue scrollbar styling and remove redundant padding
- Set Vite server to listen on all network interfaces
