nounCountsByType (read by stats().entitiesByType / counts.byTypeEnum) was
incremented in saveNoun_internal(), which runs on every noun write — including
the HNSW index re-saving a node whenever its neighbor links change. So per-type
counts grew with graph connectivity instead of entity count (an internal report
saw 8 documents read as 44). Moved the increment into saveNounMetadata_internal(),
gated on isNew + visibility, exactly parallel to the authoritative total; the
visibility-flip path adjusts it in lockstep too.
Tests: tests/unit/storage/stats-count-accuracy.test.ts (30 dense-type entities ->
exactly 30 across stats/counts/getNounCount) + de-theatricalized the >=2 assertion
in brainy-core.unit.test.ts to exact equality. Build green; 1455 unit green.
Part of the 8.0 readiness audit Phase 1; cold-reopen count rehydration is still WIP.
