chore: scaffold tracks and tooling

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

js/test/m00-sanity.test.js

@@ -0,0 +1,16 @@
+import test from 'node:test'
+import assert from 'node:assert/strict'
+import { loadFixture, freeze } from './helpers.js'
+
+test('m00 arithmetic', () => assert.equal(1 + 1, 2))
+
+test('m00 fixture loads and cases hold', () => {
+  const fx = loadFixture('m00-sanity')
+  assert.equal(fx.function, 'sanity')
+  fx.cases.forEach((c) => assert.equal(c.args[0] + c.args[1], c.expected, c.name))
+})
+
+test('m00 freeze is deep', () => {
+  const o = freeze({ a: { b: [1] } })
+  assert.ok(Object.isFrozen(o.a) && Object.isFrozen(o.a.b))
+})