v6 changelog

I've been meaning to de-cheese campaign levels and mess around with custom puzzles and new custom element ideas, but I'm a bit short on the kind of time and brainpower that would need. For now, I'll keep you up to date with the following:

**v6 (25th April 2024):**

* Custom puzzles; Fixed a bug where moves that had only voidlike effects weren't recorded in the replay. Also made redos work better in voidlike puzzles. May still be bugs.

* Relax height threshold for half zoom in custom puzzles by 2 tiles.

* Fix level editor tab picking being broken if you're zoomed out.

* Community Levels chapters are now broken up by author, seems the most logical for now as every author's style is for now totally different. Added 11 of them and decheese-fixed a 12th.