Pin the epub skill's test-only dependencies (EbookLib, beautifulsoup4) with
exact versions in requirements-epub-test.txt and install from that file in
CI, instead of unpinned package names. The file is test-only and notes that
EbookLib is AGPL; requirements-dev.txt is untouched.
Also surface the epublib skip in epub/scripts/test_epub_skill.sh: when
epublib is not importable (it requires Python 3.13+), epub-edit and
epub-convert now print an explicit SKIPPED line and count as SKIP in the
summary instead of silently passing.
Co-authored-by: factory-droid[bot] <138933559+factory-droid[bot]@users.noreply.github.com>
Magnus Hedemarkandfactory-droid[bot] <138933559+factory-droid[bot]@users.noreply.github.com>