content/diff + diff-versions enumerated ids top-level only (doc-ids/
doc-find), so diffs of documents with sections missed every nested add/
remove/change. Now via doc-tree-ids + doc-deep-find; sections excluded from
:changed (no own content), still reported in :added/:removed. Flat-doc
diffs unchanged. +9 store tests.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>