Cannot put image occlusion mask right at the edge of the image

[abdnh]

Windows 10, Anki version ⁨24.11 (97e6b3d)⁩, release candidate.

Steps to reproduce:

Zoom in as much as possible when making/editing an IO card.
Try to make an occlusion such that its edge is touching the edge of the image itself.
The edge of the occlusion doesn’t touch the edge of the image, there is a gap.

Originally reported on https://forums.ankiweb.net/t/io-bug-cant-put-an-occlusion-right-at-the-edge-of-an-image/51982

[abdnh]

Might be related to this: #2588

Though as noted in the forums, the behavior is different on stable.