- Use slightly different hue of green to distinguish from difficulty
control points. The colour is still not ideal, but picking
a distinctive enough hue is pretty hard.
- Place the preview time part at the bottom rather at the top.
Not sure why it was at the top; not only could it overlap with the
control points, but it also looked quite badly misaligned there
when bookmarks were displayed at the bottom.
As pointed out in https://github.com/ppy/osu/discussions/16435, beatmaps
with too many control points (usually added via external automation
apps) could cause the lazer editor to grind to a halt.
The overheads here are mostly from the GL side. An eventual goal would
be to render this in a smarter way, rather than using thousands of
drawables. Until that, this optimisation should help reduce the overhead
by omitting control points in close proximity that are redundant for
display purposes.
I've tried to contain this in the display logic directly, with the goal
that it can be ripped out as fast as it was added. Certainly required
more changes than I hoped for, but I don't think it's too ugly.