Freeze: Copy / Paste

### Details
Copy + Paste [this JSON document](https://github.com/javascripture/javascripture/blob/gh-pages/bibles/NMV.json?raw=true)

As a result, the app will freeze (and might crash after relaunch).

h/t @scruffian (Thank you for reporting this one Ben!!)

Start by copying the linked NMV.json document and pasting it into the macOS app to reproduce the freeze and check whether relaunch is affected. The issue names no implementation file or test, so trace the paste handling entry point and add a regression check showing that this document no longer freezes or crashes the app.

Written by the indexing model from the issue text.