On a fresh ocr_cache volume /app/cache/.tmp does not exist yet. The mkdir
ensures the first Surya model download can proceed without ENOSPC on the
512 MB /tmp tmpfs. The find cleanup removes fragments left by docker-kill
mid-download, preventing cross-job ground-truth leakage.
Fixes#614. See ADR-021.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
