[Feature] Free layout sub-canvas hopes to support batch drag and drop

[plasma-crimson]

对应插件 free-container-plugin
多选节点时，希望能够批量拖入子画布内，目前只能单个节点拖入

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Corresponding plug-in free-container-plugin
When selecting multiple nodes, I hope to be able to drag them into the sub-canvas in batches. Currently, only a single node can be dragged in.