Have you tried the following...
Applied Effects Tab at right of interface
Applied Effects Palette
Motion Panel expanded
and the go to Rotation in that Motion Panel expanded...use slider or type in degrees accordingly.
Right click the clip
select Rotate 90 degree left or Rotate 90 degree right as many time as necessary to get your 180 degrees.
Please let us know if any of that worked for you.
Thank you. That worked fine in the Expert view but why doesn't the Projct Asset image also rotate?
Glad that worked for you in the Expert view Timeline.
The Project Assets has only copies of the source media, and those copies all link back to the source media at their hard drive save location.
Once you drag a photo or video from Project Assets, the editing of the photo or video on the Timeline is not reflected in the Project Assets thumbnails. The only exception to that rule seems logical, that is, when you create a title in the program's Titler, edit that title in the Titler, and close the Titler, leaving the edited title file on the Timeline, what you see in Project Assets is a thumbnail for that title with all its up to date edits.
If you are interested in going deeper into this train of thought, an interesting tour is the Replace Footage feature.