How to add list on grid(editable) as shown on screen?
OOTB Grid will be not helpful here.
You can try with extensions like:
Smart Grid Property <- This should work!
You can also use Standard Repeater Widget.
How can we use in grid?
You cannot use repeater in Grid. You can mock your row as a completely new Mashup and then use repeater to make a "Grid" with it.
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