Two features in this commit:
1. Knowledge Graph context now flows into test generation pipeline.
When `aqe code index .` populates vectors, test generation produces
+78% more assertions and +2.9% higher coverage estimates by using
KG dependency and semantic similarity data.
2. Replaced pure JS HNSW index with RuvectorFlatIndex backed by
@ruvector/gnn (Rust/NAPI). Vector loading drops from 16-18s to 65ms
(276x faster), recall improves from 70% to 100%, memory drops 3.4x,
and per-query search stays comparable (3.4ms vs 2.3ms).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>