convert.py: Pillow's PDF writer requires libjpeg for RGB images, which
is not available in the CI Python environment. Replace all Pillow PDF
saves with _save_images_as_pdf(), which writes pages as lossless PNGs
and assembles them with qpdf — no JPEG dependency needed.
build.yml: install mkdocs-material[imaging] instead of mkdocs-material
to satisfy the cairosvg dependency required by the social plugin.
Signed-off-by: nopeitsnothing <no@anonymousplanet.org>
Replaces the broken --prefers-color-scheme=dark Chromium flag with a
pixel-level converter. Rasterizes pages via pdftoppm, remaps colors to
the hacker theme (#1f1f31 bg, #e0e0e0 text, #5e8bde links), and
reassembles with qpdf. Processes in batches of 50 pages to avoid OOM
on large documents like the 414-page guide.
Signed-off-by: nopeitsnothing <no@anonymousplanet.org>
nopeitsnothing