Preserve notes and handout master export, visible text and native parallel
compression while propagating shared font errors through each export path.
Keep the dependency check accurate for native and WASM feature resolution.
PR #708.
krilla compressed each slide's print-resolution artwork on the export
thread; with its rayon feature (desktop only) the deflate runs in the
background while the next slide renders. The rendered pixels are also
moved into the image instead of copied.
skylar taylor-barrick