TextPack and Panda support

[patrickrushton]

It would be great to have support for:

• TextPack, which I understand to be a zipped TextBundle
• Panda, which I understand to be a .textpack with the extension renamed to .panda

[ttscoff]

What app creates .panda files?

[patrickrushton]

Panda https://bear.app/panda/