This barely qualifies as an answer in its own right: the method is the same as @quellenform's, here The only difference in this answer, is that the sorting method is packed into a group for re-use, and the choice of weight by which to sort.
This group, given a weight, will capture the sorted indices of points on the points themselves:
It creates a dummy Curve Line with the same number of points as the incoming geometry, for the sole purpose of using Curve Topology's Points of Curve node, which, given weights, can return sorted indices. It transfers the weights from the incoming geometry to the curve by index, returns the sorted indices back to the incoming geometry's points (by index), and captures them.
The group can be used to sort anything on mesh points; here, clockwise viewed from positive Z, by feeding it [1- a Radial texture] as the weight:
Transforming the point-cluster on the left to the point-cluster on the right:
Point 0 could be moved around by rotating the texture, or adding to the sorted index, modulo (point-count)
