Check the selected S3 storage against the database at submit time so
stale Livewire state cannot schedule backups with storage that was
reassigned or marked unusable after the component mounted.
Prevent scheduled database backups from enabling S3 uploads without a valid team-owned storage configuration, and preserve the previous S3 storage ID in missing-storage error messages.
Add coverage for backup edit/create validation and S3 upload failure messaging.
Andras Bacsai