In-Memory vector search engine & HNSW ANN graph in Java 21 Loom with sub-millisecond KNN retrieval, 8-bit scalar quantization, and 16,000+ QPS; vectra-core project shows high throughput on Java 21 loom

Original headline: "ronitgupta138/vectra-core: ⚡ In-Memory Vector Search Engine & HNSW ANN Graph in Java 21 Loom. Sub-millisecond KNN retrieval, 8-bit scalar quantization (SQ8), 16,000+ QPS."