🐿️ Add daily sync to 6AM checkup

The checkup was health-check only — it reported status but never synced.
If fswatch missed a change, skills wouldn't back up until next file edit.
Now the 6AM checkup runs do_sync_locked before reporting, ensuring at least
one daily backup regardless of fswatch activity.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Gregg Cochran

groundhog

@@ -385,6 +385,11 @@ cmd_checkup() {
     fi
   fi
 
+  # 10. Daily sync — ensure skills are backed up even if fswatch missed changes
+  log "🐿️  daily sync triggered by checkup"
+  do_sync_locked
+  report+="✅ Daily sync: completed\n"
+
   report+="\n────────────────────────────────────\n"
 
   if [[ "$issues" -eq 0 ]]; then