Allow copying and pasting different things
We should allow pasting things from the clipboard. We should do it in a way that Drawy can detect the type of the item you're pasting:
1. If it's an image, paste it as an image (once we have image support)
2. If it's plain text, paste it as a TextItem.
3. If it's an item copied from Drawy itself, paste it as an Item. When copying items, we'd need to copy their serialized content as a JSON string. When pasting, we'd need to determine if the pasted content is a valid JSON string _and_ if it's made by Drawy. If you want to support pasting copied items from excalidraw/tldraw/inkscape, we'd need to identify them as well.
task