- Coalesced pointer reads: the pointer-list read path (covered queries and
  any multi-pointer fetch) reads each shard's records in coalesced,
  offset-sorted passes over a sliding window instead of one pread per record.
- Sort pushdown via the sort-field index: a limited query sorting on an
  indexed field unaligned with a fully index-answered predicate walks the
  sort index in order, filtered by the predicate's pointer set — the page
  comes out already sorted, no in-memory sort or key-extraction pass. Falls
  back to the in-memory sort when it does not apply; results are identical.

Patch release: no public API changes. 121/121 tests green.