Replace blocking subprocess.run calls in run_git_command and get_commits_by_day with async subprocess execution using asyncio.create_subprocess_exec and proc.communicate. Update process_repo's git clone call to use the same async pattern, ensuring the entire git operations pipeline runs non-blocking in the event loop.
The README installation instructions now point to the correct Git repository at
retoor.molodetz.nl/retoor/zhurnalweb and use the updated directory name
zhurnalweb instead of the placeholder URL and old directory name.
