rawler's allocation guard is sized in samples but worded in pixels, and
a linear DNG passes width × 3. A 22927 × 8966 Lightroom panorama was
refused as ">50000 px wide", and develop fell back silently to the
embedded preview. Route rawler through third_party with the guard at
1.5 G samples and 200 000 per axis.
The crate as crates.io publishes it, minus .cargo-ok, its Cargo.lock and
data/testdata (13 MB of sample files only its own tests read). Not yet
routed through [patch.crates-io]; the next commit is the patch.