fix(package.json): correct Windows sqlite-vec package name + add linux-arm64

[ilepn]

Summary

• Renames sqlite-vec-win32-x64 → sqlite-vec-windows-x64 in optionalDependencies (the old name doesn't exist on npm — 404)
• Adds missing sqlite-vec-linux-arm64 entry to match all 5 platforms declared in sqlite-vec's own optionalDependencies

Fixes #224

Root Cause

The sqlite-vec npm package maps process.platform value win32 → windows in its platformPackageName() function. The published npm package is sqlite-vec-windows-x64, not sqlite-vec-win32-x64.

Verification

Tested on Windows 11 x64, Node.js v25.6.1:

1. Package name confirmation:

$ npm view sqlite-vec-win32-x64
npm error code E404 — does not exist

$ npm view sqlite-vec-windows-x64 version
0.1.7-alpha.2 ✓

2. Extension loading works:

$ node -e "const sv = require('sqlite-vec'); console.log(sv.getLoadablePath())"
C:\...\node_modules\sqlite-vec-windows-x64\vec0.dll ✓

3. Full round-trip (load → create table → insert → KNN query):

const Database = require('better-sqlite3');
const sqliteVec = require('sqlite-vec');
const db = new Database(':memory:');
sqliteVec.load(db);

db.exec(`CREATE VIRTUAL TABLE vectors_vec USING vec0(
  hash_seq TEXT PRIMARY KEY,
  embedding float[4] distance_metric=cosine
)`);

const ins = db.prepare('INSERT OR REPLACE INTO vectors_vec (hash_seq, embedding) VALUES (?, ?)');
ins.run('abc_0', new Float32Array([1, 0, 0, 0]));
ins.run('def_0', new Float32Array([0.9, 0.1, 0, 0]));

const results = db.prepare(
  'SELECT hash_seq, distance FROM vectors_vec WHERE embedding MATCH ? AND k = 2'
).all(new Float32Array([1, 0, 0, 0]));

// → [{ hash_seq: 'abc_0', distance: 0 }, { hash_seq: 'def_0', distance: 0.00611... }] ✓

4. qmd status confirms sqlite-vec operational:

$ qmd status
Documents
  Total:    1055 files indexed
  Vectors:  1145 embedded  ✓

5. sqlite-vec's own optionalDependencies (all 5 platforms):

{
  "sqlite-vec-darwin-x64": "0.1.7-alpha.2",
  "sqlite-vec-darwin-arm64": "0.1.7-alpha.2",
  "sqlite-vec-linux-arm64": "0.1.7-alpha.2",
  "sqlite-vec-linux-x64": "0.1.7-alpha.2",
  "sqlite-vec-windows-x64": "0.1.7-alpha.2"
}

qmd previously listed only 4, missing linux-arm64 and using wrong Windows name.

Test plan

• npm install on Windows x64 — no 404 warning for sqlite-vec
• npm install on Linux arm64 — sqlite-vec binary installs
• qmd embed + qmd vsearch on Windows — vector search works
• Existing CI/tests pass (change is package.json only, no code changes)