fix(group): preserve children + size on edit, fix status WS proxy

- Skip NodeModal on double-click for 'group'/'groupRect' (use inline rename)
- Exempt 'group' from properties-clears-height rule in updateNode
  (was collapsing group + hiding children with extent: 'parent')
- Enable ws: true on Vite /api proxy so /api/v1/status/ws/status upgrades
  (status bubbles stayed grey because WS handshake failed)
- Add regression tests for group/groupRect height preservation

frontend/src/stores/canvasStore.ts

@@ -209,7 +209,7 @@ export const useCanvasStore = create<CanvasState>((set) => ({
         if (n.id !== id) return n
         const updated: Node<NodeData> = { ...n, data: { ...n.data, ...data } }
         // When properties change, clear stored height so the node auto-sizes to fit new content
-        if ('properties' in data && n.data.type !== 'proxmox' && n.data.type !== 'groupRect') {
+        if ('properties' in data && n.data.type !== 'proxmox' && n.data.type !== 'groupRect' && n.data.type !== 'group') {
           updated.height = undefined
         }
         if ('parent_id' in data) {