fix: reconcile instance status with Docker on list, add IsContainerRunning

internal/docker/container.go

@@ -246,6 +246,15 @@ func (c *Client) ListContainers(ctx context.Context, labelFilters map[string]str
 	return result, nil
 }
 
+// IsContainerRunning checks if a container is in the "running" state.
+func (c *Client) IsContainerRunning(ctx context.Context, containerID string) (bool, error) {
+	inspectResult, err := c.api.ContainerInspect(ctx, containerID, client.ContainerInspectOptions{})
+	if err != nil {
+		return false, err
+	}
+	return inspectResult.Container.State != nil && inspectResult.Container.State.Running, nil
+}
+
 // InspectContainerPort returns the host port mapped to a given container port.
 // This is useful after starting a container with auto-assigned ports.
 func (c *Client) InspectContainerPort(ctx context.Context, containerID string, containerPort string) (uint16, error) {