Enhance hourly-git-sync script to skip empty commits

[Stoff81]

Only push git backups if there are changes

[chrysb]

Nice improvement 👍

Quick question: have you actually observed empty commits happening in this flow? A plain git commit shouldn’t create one unless --allow-empty is used, so I want to make sure we’re fixing a real behavior we’ve seen.

One risk to call out: the current check uses git diff --quiet and git diff --cached --quiet, which won’t detect untracked files. That means the script could exit early even when new files exist.

[Stoff81]

Empty commit here:

Its possible these commits where caused from non-tracked files. These are all my additions to .openclaw/.gitignore

`.alphaclaw/*
agents/
canvas/
completions/
credentials/
cron/
devices/
identity/
logs/
media/
memory/
sandbox/
sandboxes/
subagents/
workspace/

*/user-data/
/user-data/
browser/openclaw/user-data

openclaw.json.bak*`