When horizon-prepare failed, vanilla-data.sh deleted the preparation folder but kept what it had
already written to .local/ (horizon-client, horizon-client-motion, ...). The next job then saw those
real folders as already there: its preparation listed only horizon-client-structures in .entries,
and the checkout kept using the stale resources outside the per-key cache.
Now a failed preparation removes the .local/ entries it created; a job first removes real folders
named like preparation outputs, and makes again a preparation whose .entries lacks horizon-client.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Ludovic Marie
160c1e8b7a