add maintenance mode

internal/httpapp/diagnostics_handlers.go

@@ -198,6 +198,16 @@ func (a *App) handleHealthCheck(w http.ResponseWriter, r *http.Request) {
 		health.Checks["iscsi"] = "healthy"
 	}
 
+	// Check maintenance mode
+	if a.maintenanceService != nil && a.maintenanceService.IsEnabled() {
+		health.Checks["maintenance"] = "enabled"
+		if health.Status == "healthy" {
+			health.Status = "maintenance"
+		}
+	} else {
+		health.Checks["maintenance"] = "disabled"
+	}
+
 	// Set HTTP status based on health
 	statusCode := http.StatusOK
 	if health.Status == "unhealthy" {