expand container monitoring functionality (#928)

- Add new /containers route with virtualized table showing all containers across systems
- Implement container stats collection (CPU, memory, network usage) with health status tracking
- Add container logs and info API endpoints with syntax highlighting using Shiki
- Create detailed container views with fullscreen logs/info dialogs and refresh functionality
- Add container table to individual system pages with lazy loading
- Implement container record storage with automatic cleanup and historical averaging
- Update navbar with container navigation icon
- Extract reusable ActiveAlerts component from home page
- Add FooterRepoLink component for consistent GitHub/version display
- Enhance filtering and search capabilities across container tables

agent/server.go

@@ -168,6 +168,8 @@ func (a *Agent) handleSSHRequest(w io.Writer, req *common.HubRequest[cbor.RawMes
 		switch v := data.(type) {
 		case *system.CombinedData:
 			response.SystemData = v
+		case string:
+			response.String = &v
 		default:
 			response.Error = fmt.Sprintf("unsupported response type: %T", data)
 		}