Bug: after a whole Excel finishes, re-selecting it shows an empty preview
sample-row dropdown because _reload_sample_rows uses load_outfit_tasks (which
skips 完成 rows). Preview should list all valid data rows regardless of status.
Document the cause + fix (new excel_service.read_all_rows for preview; generate
still uses load_outfit_tasks). Update §7 + add §10.3 / §19.9.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>