Bounds the originals cache and evicts least-recently-used. cacheOriginalsMaxBytes default 100 GiB; the effective limit adapts down via fs.statfs to keep freeBelowBytes (default 50 GiB) free. Over-limit writes evict unpinned originals oldest-mtime-first (mtime touched on read); pinned files (favorites + latest week) are skipped and an over-budget on-demand fetch proceeds over-limit. Every in-flight write is excluded from eviction, so concurrent fetches never delete each other's just-stored file. Only cacheDirectory/originals is evicted; downloadDirectory and thumbnails never.
Model: opus-4-8
