fix(canvas): keep container host height when editing an unrelated field

Editing any field on a container-mode vm/lxc/docker_host node (e.g. just
renaming it or adding a property) reset its manually-set height to
undefined, snapping the container back to auto-fit content size and
scrambling/overflowing its nested children.

Root cause: updateNode clears height on every 'properties' change and the
node modal always includes properties in its payload. Only proxmox was
excluded from the reset; vm/lxc/docker_host in container mode were not.

- export CONTAINER_MODE_TYPES from virtualEdgeParent (reuse, no re-declare)
- updateNode: skip the height reset for any container-mode host type;
  proxmox stays always-excluded (legacy), plain leaf nodes still auto-fit
- regression tests: manual height preserved for container-mode
  vm/lxc/docker_host and proxmox; still reset for a non-container vm

Fixes #278

ha-relevant: yes

frontend/src/utils/virtualEdgeParent.ts

@@ -2,7 +2,7 @@ import type { NodeData } from '@/types'
 
 export type NodeType = NodeData['type']
 
-const CONTAINER_MODE_TYPES = new Set<NodeType>(['proxmox', 'vm', 'lxc', 'docker_host'])
+export const CONTAINER_MODE_TYPES = new Set<NodeType>(['proxmox', 'vm', 'lxc', 'docker_host'])
 const DOCKER_CONTAINER_PARENT_TYPES = new Set<NodeType>(['docker_host', 'lxc', 'vm', 'proxmox'])
 
 export interface VirtualEdgeEndpoint {