- No reduced Rect in march square algorithm, it was causing inconsistent cases near the borders and made the outline less accurate
- Ignore invalid generated polygons (under 3 points) to avoid unnecessary errors and crashes
- Error popup only when no polygon could be generated at all
- Added option to shrink pixels (to get rid of small separate islands)
- Fixed polygon preview (lines were sometimes not showing along the borders)

Fixes #32564, #29267