My Backup Failed Twice: Docker Permissions, Then GitHub's 2 GiB Limit

When you automate backups, you eventually discover the backup was not the hard part. The hard part was everything around it. This week I got a nice little reminder from my self-hosted agent setup: the backup job can be logically correct, authenticated, scheduled, and still fail because of two very boring constraints: Docker-owned files are not always readable by the user running cron. GitHub Release assets have a hard-ish practical ceiling around 2 GiB per uploaded asset. Neither problem was exo