fix: make grocery and reference ordering deterministic

Every list query lacked a tiebreak, so rows sharing a sort key (same-ms
createdAt inserts, tied or NULL quality scores) came back in unspecified
order and bestRef flipped between loads. Add explicit tiebreaks: items
createdAt desc, id desc (newest first); references qualityScore desc,
id asc (first inserted wins ties). Categories were already total
(order, name unique).

Pin the rules with service tests.

0 files changed, 0 insertions, 0 deletions