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

src/brainy.ts

@@ -6,8 +6,8 @@
  */
 
 import { v4 as uuidv4 } from './universal/uuid.js'
-import { HNSWIndex } from './hnsw/hnswIndex.js'
-// TypeAwareHNSWIndex removed from default path — single unified HNSWIndex is faster
+import { JsHnswVectorIndex } from './hnsw/hnswIndex.js'
+// TypeAwareHNSWIndex removed from default path — single unified JsHnswVectorIndex is faster
 // for the 99% of queries that don't filter by type (avoids searching 42 separate graphs)
 import { createStorage } from './storage/storageFactory.js'
 import { BaseStorage } from './storage/baseStorage.js'
@@ -156,7 +156,7 @@ export class Brainy<T = any> implements BrainyInterface<T> {
   private static instances: Brainy[] = []
 
   // Core components
-  private index!: HNSWIndex
+  private index!: JsHnswVectorIndex
   private storage!: BaseStorage
   private metadataIndex!: MetadataIndexManager
   private graphIndex!: GraphAdjacencyIndex
@@ -606,8 +606,8 @@ export class Brainy<T = any> implements BrainyInterface<T> {
       // Wire the mmap-vector backend (2.4.0 #2). When the vectorStore:mmap
       // provider is registered AND the storage adapter resolves a real local
       // path via getBinaryBlobPath(), open the mmap file there and inject the
-      // backend into HNSWIndex. Cloud adapters return null and skip silently;
-      // HNSWIndex's behaviour is then identical to pre-2.4.0 (per-entity reads
+      // backend into JsHnswVectorIndex. Cloud adapters return null and skip silently;
+      // JsHnswVectorIndex's behaviour is then identical to pre-2.4.0 (per-entity reads
       // from canonical storage). Failures are non-fatal — the index still
       // works, just without the zero-copy fast path.
       await this.wireMmapVectorBackend()
@@ -8324,7 +8324,7 @@ export class Brainy<T = any> implements BrainyInterface<T> {
    * @param candidateIds Optional pre-resolved metadata filter IDs for metadata-first search.
    *   When provided, HNSW search is restricted to these candidates:
    *   - NativeHNSWWrapper: uses native searchWithCandidates (Rust bitmap filtering)
-   *   - JS HNSWIndex: converts to filter function with O(1) Set lookups
+   *   - JS JsHnswVectorIndex: converts to filter function with O(1) Set lookups
    */
   private async executeVectorSearch(params: FindParams<T>, candidateIds?: string[]): Promise<Result<T>[]> {
     const vector = params.vector || (await this.embed(params.query!))
@@ -9070,7 +9070,7 @@ export class Brainy<T = any> implements BrainyInterface<T> {
    * - Cloud storage (GCS/S3/R2/Azure): 'deferred' for 30-50x faster adds
    * - Local storage (FileSystem/Memory/OPFS): 'immediate' (already fast)
    */
-  private setupIndex(): HNSWIndex {
+  private setupIndex(): JsHnswVectorIndex {
     const indexConfig = {
       ...this.config.index,
       distanceFunction: this.distance,
@@ -9085,7 +9085,7 @@ export class Brainy<T = any> implements BrainyInterface<T> {
 
     const persistMode = this.resolveHNSWPersistMode()
 
-    return new HNSWIndex(indexConfig as any, this.distance, {
+    return new JsHnswVectorIndex(indexConfig as any, this.distance, {
       storage: this.storage,
       useParallelization: true,
       persistMode
@@ -9106,11 +9106,11 @@ export class Brainy<T = any> implements BrainyInterface<T> {
    *    - The metadata index has a stable `idMapper`.
    *    - `config.index.type !== 'hnsw'` (no explicit opt-out).
    * 3. `'hnsw'` provider if registered (cortex's native HNSW).
-   * 4. Brainy's built-in TS HNSWIndex (the always-available fallback).
+   * 4. Brainy's built-in TS JsHnswVectorIndex (the always-available fallback).
    *
    * See ADR-002 in the cortex repo for the engagement rationale.
    */
-  private createIndex(): HNSWIndex {
+  private createIndex(): JsHnswVectorIndex {
     const persistMode = this.resolveHNSWPersistMode()
     const indexType = (this.config.index as any)?.type as 'hnsw' | 'diskann' | undefined
 
@@ -9170,7 +9170,7 @@ export class Brainy<T = any> implements BrainyInterface<T> {
   private instantiateDiskAnn(
     factory: (config: any, distance: DistanceFunction, options: any) => any,
     persistMode: 'immediate' | 'deferred'
-  ): HNSWIndex {
+  ): JsHnswVectorIndex {
     const storageWithBlob = this.storage as unknown as {
       getBinaryBlobPath?: (key: string) => string | null
     }
@@ -9377,7 +9377,7 @@ export class Brainy<T = any> implements BrainyInterface<T> {
   }
 
   /**
-   * @description Open the mmap-vector backend and inject it into HNSWIndex.
+   * @description Open the mmap-vector backend and inject it into JsHnswVectorIndex.
    * Called once during init after plugin activation, metadataIndex init, and
    * graphIndex setup — so the idMapper is available and providers are wired.
    *
@@ -9397,7 +9397,7 @@ export class Brainy<T = any> implements BrainyInterface<T> {
    * (or a re-open) sees the correct value.
    *
    * Failures here are non-fatal: a debug-level log records the reason, and
-   * HNSWIndex continues without the mmap fast path.
+   * JsHnswVectorIndex continues without the mmap fast path.
    */
   private async wireMmapVectorBackend(): Promise<void> {
     const provider = this.pluginRegistry.getProvider<VectorStoreMmapProvider>('vectorStore:mmap')