tools/manual_diff.py: word-level diff of one manual between two doc folders.
version-differences.md: the 20 manuals whose revision tables list only
contact information were diffed; E10 and E30 have real content changes,
the rest wording only. CLAUDE.md: re-checks use the full diff.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
