How to move markers from Source Panel to top of Timeline Panel? (No markers on clip itself)

Unfortunately, Clip and Sequence markers are different so there's no native automatic way to just copy them over from one to the other. But you should be able to manually do it easily enough. As long as the clip is deselected in the timeline panel you should be able to just spam:

Shift + M - to jump to the next marker in the sequence

M - to create the new marker on the sequence

Not too bad.

If you really wanted to and you had the software to make a macro you could get it down to one key, but since this may only be a one-time thing then you may as well just get through it manually this time around.