tests/make_word_test_files.py regenerates three fixtures:
- tests/word_test_input.docx - tagged mini manuscript (book start through
req review, all section roles, <<<>>> scene breaks)
- tests/word_test_output.docx - output of format_document() on the above
- tests/python_docx_control.docx - untouched python-docx save (baseline)
Purpose: bisect the Word-open failure. The full manuscript output is
structurally clean by every OOXML check (package rels, content types,
sectPr/settings ordering, header/footer parts, fields, hyperlinks, custom
parts all validate); the fixtures let Word itself tell us whether the
pipeline or the manuscript content is the trigger.
