refactor(8.0): rename HNSWIndex class → JsHnswVectorIndex (scaffold step 3)

Step 3 of the brainy 8.0 rename scaffolding. The class name now matches
its role: the JS HNSW implementation of the VectorIndexProvider contract.
Per planning § 2.3: this is NOT cosmetic — leaving HNSWIndex when the
public contract is VectorIndexProvider creates a confusing read at the
implementation layer.

CHANGES

Repo-wide mechanical rename: HNSWIndex → JsHnswVectorIndex across 52
references in src/ + 5 references in tests/ via sed. Class declaration,
imports, JSDoc, comments, and identifiers all updated.

src/index.ts
- Primary public export: JsHnswVectorIndex (the new name).
- Backwards-compat alias: `export const HNSWIndex = JsHnswVectorIndex`
  with @deprecated note. Removed in the final 8.0 cleanup commit.

NO-OP scope

No behavioural change. The class is exactly the same; only the name
moved. Tests + build green.

VERIFICATION

- npx tsc --noEmit: clean
- npm test: 1468 / 1468 unit

tests/unit/hnsw/lazy-vectors.test.ts

@@ -11,7 +11,7 @@
 
 import { describe, it, expect, beforeEach } from 'vitest'
 import { v4 as uuidv4 } from 'uuid'
-import { HNSWIndex } from '../../../src/hnsw/hnswIndex.js'
+import { JsHnswVectorIndex } from '../../../src/hnsw/hnswIndex.js'
 import { euclideanDistance } from '../../../src/utils/index.js'
 import { MemoryStorage } from '../../../src/storage/adapters/memoryStorage.js'
 
@@ -43,12 +43,12 @@ describe('Lazy Vector Loading (B2)', () => {
   // 1. LAZY MODE: VECTOR EVICTION
   // =================================================================
   describe('vector eviction in lazy mode', () => {
-    let index: HNSWIndex
+    let index: JsHnswVectorIndex
     let storage: MemoryStorage
 
     beforeEach(async () => {
       storage = new MemoryStorage()
-      index = new HNSWIndex(
+      index = new JsHnswVectorIndex(
         {
           M: 8,
           efConstruction: 100,
@@ -116,7 +116,7 @@ describe('Lazy Vector Loading (B2)', () => {
   describe('memory mode retains vectors (default)', () => {
     it('should keep vectors in memory by default', async () => {
       const storage = new MemoryStorage()
-      const index = new HNSWIndex(
+      const index = new JsHnswVectorIndex(
         { M: 4, efConstruction: 50, efSearch: 20 },
         euclideanDistance,
         { useParallelization: false, storage }
@@ -135,7 +135,7 @@ describe('Lazy Vector Loading (B2)', () => {
 
     it('should work without storage adapter in memory mode', async () => {
       // No storage adapter provided
-      const index = new HNSWIndex(
+      const index = new JsHnswVectorIndex(
         { M: 4, efConstruction: 50, efSearch: 20 },
         euclideanDistance,
         { useParallelization: false }
@@ -157,7 +157,7 @@ describe('Lazy Vector Loading (B2)', () => {
   describe('lazy mode without storage', () => {
     it('should not evict vectors when no storage adapter is configured', async () => {
       // vectorStorage: 'lazy' but no storage — vectors should stay in memory
-      const index = new HNSWIndex(
+      const index = new JsHnswVectorIndex(
         {
           M: 4,
           efConstruction: 50,
@@ -185,7 +185,7 @@ describe('Lazy Vector Loading (B2)', () => {
   describe('lazy mode with quantization', () => {
     it('should use SQ8 for traversal and load full vectors for rerank', async () => {
       const storage = new MemoryStorage()
-      const index = new HNSWIndex(
+      const index = new JsHnswVectorIndex(
         {
           M: 8,
           efConstruction: 100,
@@ -221,7 +221,7 @@ describe('Lazy Vector Loading (B2)', () => {
 
     it('should return results sorted by exact distance after rerank', async () => {
       const storage = new MemoryStorage()
-      const index = new HNSWIndex(
+      const index = new JsHnswVectorIndex(
         {
           M: 8,
           efConstruction: 100,
@@ -257,7 +257,7 @@ describe('Lazy Vector Loading (B2)', () => {
   describe('multiple searches in lazy mode', () => {
     it('should handle repeated searches correctly', async () => {
       const storage = new MemoryStorage()
-      const index = new HNSWIndex(
+      const index = new JsHnswVectorIndex(
         {
           M: 8,
           efConstruction: 100,

tests/unit/hnsw/quantization.test.ts

@@ -21,7 +21,7 @@ import {
   serializeSQ8,
   deserializeSQ8
 } from '../../../src/utils/vectorQuantization.js'
-import { HNSWIndex } from '../../../src/hnsw/hnswIndex.js'
+import { JsHnswVectorIndex } from '../../../src/hnsw/hnswIndex.js'
 import { euclideanDistance } from '../../../src/utils/index.js'
 import { MemoryStorage } from '../../../src/storage/adapters/memoryStorage.js'
 
@@ -286,14 +286,14 @@ describe('SQ8 Quantization', () => {
   // 4. HNSW SEARCH WITH QUANTIZATION
   // =================================================================
   describe('HNSW search with quantization', () => {
-    let index: HNSWIndex
+    let index: JsHnswVectorIndex
     let storage: MemoryStorage
     const dim = 32 // Small dimension for fast tests
     let ids: string[]
 
     beforeEach(async () => {
       storage = new MemoryStorage()
-      index = new HNSWIndex(
+      index = new JsHnswVectorIndex(
         {
           M: 8,
           efConstruction: 100,
@@ -365,7 +365,7 @@ describe('SQ8 Quantization', () => {
   describe('two-phase rerank', () => {
     it('should accept rerank options in search', async () => {
       const storage = new MemoryStorage()
-      const index = new HNSWIndex(
+      const index = new JsHnswVectorIndex(
         {
           M: 8,
           efConstruction: 100,
@@ -399,7 +399,7 @@ describe('SQ8 Quantization', () => {
 
     it('reranked results should be sorted by exact distance', async () => {
       const storage = new MemoryStorage()
-      const index = new HNSWIndex(
+      const index = new JsHnswVectorIndex(
         {
           M: 8,
           efConstruction: 100,
@@ -432,7 +432,7 @@ describe('SQ8 Quantization', () => {
   describe('configuration defaults', () => {
     it('should disable quantization by default', async () => {
       const storage = new MemoryStorage()
-      const defaultIndex = new HNSWIndex(
+      const defaultIndex = new JsHnswVectorIndex(
         { M: 4, efConstruction: 50, efSearch: 20 },
         euclideanDistance,
         { useParallelization: false, storage }
@@ -456,7 +456,7 @@ describe('SQ8 Quantization', () => {
 
     it('should use default rerankMultiplier of 3', async () => {
       const storage = new MemoryStorage()
-      const index = new HNSWIndex(
+      const index = new JsHnswVectorIndex(
         {
           M: 4,
           efConstruction: 50,
@@ -480,7 +480,7 @@ describe('SQ8 Quantization', () => {
 
     it('should default vectorStorage to memory mode', async () => {
       const storage = new MemoryStorage()
-      const index = new HNSWIndex(
+      const index = new JsHnswVectorIndex(
         { M: 4, efConstruction: 50, efSearch: 20 },
         euclideanDistance,
         { useParallelization: false, storage }