An uncached scan probed one image at a time and read 256 KB of each. On
a NAS that is bound by per-file latency (the server/Synology: ~20 ms per
image, ~100 min for 298k images). Now chapter folders of a book and
their images are probed SCAN_CONCURRENCY (default 8, 1-64) at a time
and assembled in folder order, and imageSize() reads 32 KB first, then
256 KB, then the whole file: a prefix gives either no size or the same
size, so results do not change. Tests: every format and read stage
equals the whole-file answer; concurrency 1 and 8 build the same index
and cache; the limiter keeps its bound and per-task errors. (BL-0043)
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
MaashkinoozheandClaude Opus 5.5
5e14e54286