Crosshairs

This is really a napari issue, but I find it really hard to place the markers pixel-perfectly accurate due to the points layer cursor.
I could zoom in a lot more, but that makes the overall workflow more cumbersome as I need to constantly zoom in and zoom out again as to quickly navigate without losing the overall overview.

I think with a one line-thine translucent cross hair that is fully transparent at the centre pixel one can place points more accurately.
The same is actually true for the points themselves, they are rather large.

Again, I realize these are all napari issues but none of these have bothered me other than in this particular context of affinder.

No files, tests, or entry points are named. Start by locating the points-layer cursor and point rendering in the Python application, then determine whether the crosshair and smaller markers belong in affinder or napari. Done means point placement is easier to align pixel-perfectly without repeatedly zooming.

Written by the indexing model from the issue text.