feat: replace hnswlib-node with hnswlib-wasm for cross-platform compatibility

[kui123456789]

Summary

Replace hnswlib-node (native C++ addon) with hnswlib-wasm (WebAssembly) to eliminate the need for Visual Studio Build Tools / C++ compiler on Windows.

Problem

hnswlib-node requires native compilation via node-gyp, which demands:

• Visual Studio Build Tools (~2-3 GB download)
• Python 3
• MSVC C++ compiler

This is a significant barrier for Windows users who just want to install and use the plugin.

Solution

Replace hnswlib-node ^3.0.0 with hnswlib-wasm ^0.8.2. This is based on the author's own wasm implementation from commit d5581bb, adapted for the current v2.11.3 dual-index architecture.

Changes

package.json:

• hnswlib-node ^3.0.0 → hnswlib-wasm ^0.8.2

src/services/sqlite/hnsw-index.ts:

• Lazy async import for hnswlib-wasm module
• 3-arg constructor ("cosine", dims, maxElements) instead of separate initIndex()
• readIndex() / writeIndex() are sync (no await)
• addPoint() and searchKnn() accept Float32Array directly (removed vectorToArray() helper)

Verification

• TypeScript: npx tsc --noEmit — zero errors
• npm install — clean, no native compilation needed
• Pre-commit hooks (prettier) — passed

[Copilot]

Pull request overview

This PR swaps the HNSW vector index backend from the native hnswlib-node addon to hnswlib-wasm to avoid node-gyp/C++ toolchain requirements and improve cross-platform installability (notably on Windows).

Changes:

• Replaces hnswlib-node with hnswlib-wasm in dependencies.
• Updates the SQLite HNSW index wrapper to lazy-load the WASM module and adjust API usage (constructor, sync read/write, Float32Array inputs).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/services/sqlite/hnsw-index.ts	Switches to a lazy async import of hnswlib-wasm and updates index construction/IO and vector method calls accordingly.
package.json	Replaces the native dependency with the WASM dependency.

---

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[Copilot]

bun.lock still references hnswlib-node@3.0.0, so Bun installs may continue pulling the native addon even though package.json switched to hnswlib-wasm. Regenerate and commit the lockfile so it removes hnswlib-node and pins hnswlib-wasm@^0.8.2 instead (this is important for the Windows install story).

[Copilot]

loadHNSWLib() can trigger multiple parallel import("hnswlib-wasm") calls if several requests hit ensureInitialized() concurrently before the first import resolves. Consider caching the in-flight import (e.g., store a Promise and await it) so the module is only loaded/initialized once per process.

Suggested change

	async function loadHNSWLib(): Promise<any> {
	if (!HNSWLib) {
	const module = await import("hnswlib-wasm");
	HNSWLib = module;
	}
	return HNSWLib;
	let hnswLibPromise: Promise<any> | null = null;
	async function loadHNSWLib(): Promise<any> {
	if (HNSWLib) {
	return HNSWLib;
	}
	if (!hnswLibPromise) {
	hnswLibPromise = import("hnswlib-wasm")
	.then((module) => {
	HNSWLib = module;
	return module;
	})
	.catch((error) => {
	hnswLibPromise = null;
	throw error;
	});
	}
	return hnswLibPromise;