This is a follow up to #3: filling in the blanks from https://git-annex.branchable.com/tips/setup_a_public_repository_on_a_web_site/, I thought that only git annex get worked with http remotes. But now I think that was premature.
Investigate and make git-annex uploading work over http remotes.
Specifically this means these commands should work:
git annex sync --content
git annex copy --to origin