Thanks for testing, Joachim.
I looked at the code and it seems high quality, I liked the PKCE implementation which can be used to modernize other Cloud Services to avoid the need to store secrets and the use of system browser to avoid embedded browser limitations.
From a users point of view the ability to sync FIT files body and HRV measures is really interesting.
Unless there are objections I am willing to merge the PR as is and think about planned activities sync later, since we need to to that for all cloud services.
Cheers, Ale.