[BUG] Undo history behaves inconsistently

[hingler]

Bug Description

Undo behavior is inconsistent across toolsets, and sometimes misses commands altogether (ex. for rect select + move, lasso fill/erase)

Steps to Reproduce

1. Draw some lines
2. Fill spaces
3. Use lasso fill and lasso erase to fill arbitrary regions

Expected Behavior

Undo/redo roves step by step

Actual Behavior

Undo will sometimes skip operations, not revert changes, etc.

Additional Context

Add any other context about the problem here, such as:

• Does this happen consistently or intermittently?
• Did this work in a previous version?
• Any error messages in the browser console (F12 → Console)?

Possible Solution

Haven't looked too closely at the code. Not sure at the moment how the "undo" operation is maintaining "snapshots" of previous changes, but I figure the coverage of tool use cases is just spotty.