Main concern: The removal of the ctrlKey inversion in onStageMouseWheel likely breaks trackpad pinch-to-zoom. Browsers dispatch wheel events with ctrlKey: true for pinch gestures — that was the explicit reason for the old inversion. Now those events are ignored by the stage handler and consumed by the tool module as brush/eraser resize instead. This should be clarified with the author before merge; it's not mentioned in the PR description and looks unintentional.

Everything else (zoom math, cursor SVG, fallback behavior, snap-state interaction) checks out.
I dont have a Tablet so cant really test it on that.

@Pfannkuchensack

Thanks for calling this out. I checked the existing wheel handling more closely: the stage handler was already returning early on ctrl/meta-modified wheel events before this PR, so the old ctrlKey inversion path was dead code. The line I removed was just a small cleanup while I was already touching nearby canvas zoom code, not an intentional behavior change.

So this PR does not newly break trackpad pinch-to-zoom. That said, your broader observation is valid: ctrl/meta-modified wheel events are currently routed to brush/eraser size adjustment in the tool module, which means trackpad pinch-to-zoom does not appear to be supported today. That seems to be pre-existing behavior and is out of scope for this change.

I can revert that cleanup from this PR if we want to keep the change set strictly focused on Ctrl/Cmd+MMB zoom.