- semantic.py: normalize both None and [] doc_types to null in the metadata so a future `metadata->'doc_types' IS NULL` query counts the all-types case consistently. - test: use a fixed past date in test_occurred_at_roundtrip instead of a future literal (deterministic, no "why this date" confusion). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>