fix(scale): update drag & resize when the gridstack parent is scaled

[elmehdiamlou]

Description

When wanting to drag a grid item within a parent that is scaled using CSS transforms it doesn't work properly.

This PR serves as a solution for issue #1275 by determining the scaling factor applied to the parent to adjust the grid position and size. e.g. if the parent is scaled with scale(0.5), the scaling factor will be 2.

Additionally, here is a video demonstrating how this fix works in action.

gridstack.mp4

Checklist

• Created tests which fail without the change (if possible)
• All tests passing (yarn test)
• Extended the README / documentation, if necessary

[adumesny]

thank you for using existing code and just adding scale to it - this makes sure all existing path will continue working. wish I had not wasted so much time on @VincentMolinie review and frequent breakage....

[VincentMolinie]

Glad I could help... I was just trying to help