BRAINY-PROD-LATENCY-TRIAD Track A1 (David-approved plan): the sort path's
value resolution goes BATCHED — one chunked metadata-record batch pass
serves any N, replacing the serial per-row getNoun loop (62-98ms x 3,224
rows = the measured 199-317 second silent scan on self prod). The
metadata record carries every sortable value: system scalars EXACT
(bucketed-index precision loss can never force a per-row disk read
again) and the user bag via the shape-aware split, both record eras.
- resolveOrderValuesBatch: the one sanctioned value source for ordered
reads (batch door: getNounMetadataBatch -> getMetadataBatch -> chunked
parallel; never serial).
- Column top-K page re-sort and the no-column fallback both rewired.
- B2 down-payment: the no-column fallback ANNOUNCES itself once per
field past 500 rows - silent degradation is illegal.
- THE CALL-SHAPE PIN (tests/unit/utils/metadataIndex-sort-callshape):
zero vector-record reads, batch calls only, latency-blind so it holds
on any machine - the serial loop cannot quietly return. Ordering
contract re-pinned through the batch path (nulls last both directions,
ties by id, never drop).
(! = perf contract change only; no API change. Gates: unit 1904/1904,
integration 758, conformance 27/27.)
