package/store/themes.jsonlEvery second-order theme of every room, with its concepts.
sub, theme_id, second_order,
theme_note, n_codes (after retraction),
n_codes_coder, code_ids, items,
threads, first_hour, last_hour,
regrouped_from.
build_store.py at stage 00, from every room's
themes.jsonl.
It is the unit the scheme is built from: at B1 "the second-order
themes are read room by room" (contract §6). counts.py's
assignment_items_expected is every second-order theme of
the analysed set, "what stage B3's batches must cover".
mem.py theme and mem.py themes serve it.
Checked against: tools/build_store.py, tools/counts.py, tools/mem.py, CONTRACT-aggregator.md §6.