Show all Docker containers as sub-services with active/inactive status

Agent changes:
- Use docker ps -a to show ALL containers (running and stopped)
- Map container status: Up -> active, Exited/Created -> inactive, other -> failed
- Display Docker containers as sub-services under the docker service
- Each container shown with proper status indicator

Example display:
● docker                 active     139M     1MB
  ├─ ● docker_gitea      active
  ├─ ○ docker_old-app    inactive
  └─ ● docker_immich     active

Updated to version 0.1.173

agent/src/collectors/systemd.rs

@@ -117,8 +117,20 @@ impl SystemdCollector {
                         }
                     }
 
-                    // Docker containers are now collected as top-level services below
-                    // Keeping nginx as sub-services for now
+                    if service_name.contains("docker") && active_status == "active" {
+                        let docker_containers = self.get_docker_containers();
+                        for (container_name, container_status) in docker_containers {
+                            // For now, docker containers have no additional metrics
+                            // Future: could add memory_mb, cpu_percent, restart_count, etc.
+                            let metrics = Vec::new();
+
+                            sub_services.push(SubServiceData {
+                                name: container_name.clone(),
+                                service_status: self.calculate_service_status(&container_name, &container_status),
+                                metrics,
+                            });
+                        }
+                    }
 
                     // Create complete service data
                     let service_data = ServiceData {
@@ -140,21 +152,6 @@ impl SystemdCollector {
             }
         }
 
-        // Collect Docker containers as top-level services
-        let docker_containers = self.get_docker_containers();
-        for (container_name, container_status) in docker_containers {
-            let service_data = ServiceData {
-                name: container_name.clone(),
-                memory_mb: 0.0, // TODO: Could add container memory via docker stats
-                disk_gb: 0.0,   // TODO: Could add container disk usage
-                user_stopped: false,
-                service_status: self.calculate_service_status(&container_name, &container_status),
-                sub_services: Vec::new(),
-            };
-            agent_data.services.push(service_data.clone());
-            complete_service_data.push(service_data);
-        }
-
         // Update cached state
         {
             let mut state = self.state.write().unwrap();