The static/ directory lookup was hardcoded as a relative path from the
Quartz working directory (QUARTZ_PATH). However, ox-hugo places static
files in output_dir/static, while Quartz runs with --directory pointing
to output_dir/content.
This fix resolves static/ relative to argv.directory's parent (the
output_dir), matching where ox-hugo actually places the files. Images
referenced as /ox-hugo/... in exported markdown now display correctly.
