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

internal/hub/systems/system_manager.go

@@ -63,6 +63,15 @@ func NewSystemManager(hub hubLike) *SystemManager {
 	}
 }
 
+// GetSystem returns a system by ID from the store
+func (sm *SystemManager) GetSystem(systemID string) (*System, error) {
+	sys, ok := sm.systems.GetOk(systemID)
+	if !ok {
+		return nil, fmt.Errorf("system not found")
+	}
+	return sys, nil
+}
+
 // Initialize sets up the system manager by binding event hooks and starting existing systems.
 // It configures SSH client settings and begins monitoring all non-paused systems from the database.
 // Systems are started with staggered delays to prevent overwhelming the hub during startup.