Snap to Layer Edges or Boundary

[rich2005]

A diiferent way

In the crop tool options enable crop current layer only That constrains the crop tool to that layer.

That crops the layer. If you want to crop the whole image to the size then toggle crop current layer only off and apply the crop.

example: https://i.imgur.com/s6mym0x.mp4

edit: another 25 second demo: https://i.imgur.com/9sinhtQ.mp4