Make it so that the backpack is compatible with other types besides blocks

[BeksOmega]

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• I have searched for similar issues before opening a new one.

Component

workspace-backpack

Problem

Currently the backpack plugin is hard coded to only accept blocks into the backpack. This was fine back when the only objects that could be dragged and dropped were blocks. But now that we’ve generalized the drag system so that anything that fulfills the ISelectable and IDraggable interfaces can be dragged, it is too restrictive.

For example, this makes it impossible for the multiselect plugin to be compatible with the backpack plugin.

Request

Add an interface to the backpack plugin that it can use to check if an IDraggable should be added to the backpack.

interface Backpackable {
  toFlyoutData(): FlyoutItemInfo[];
}

Alternatives considered

N/A

Additional context

This will also require the BlockSvg in core to implement toFlyoutData.

[BeksOmega]

@HollowMan6 as a heads up!