fix(js): keep test/helpers.js free of src imports

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>

js/test/m09-runtime.test.js

@@ -4,7 +4,7 @@ import { runIO, runApp } from '../src/runtime.js'
 import { pure, draw, randomSeed, map, sequence } from '../src/io.js'
 import { view } from '../src/view.js'
 import { newGame, tick } from '../src/spawn.js'
-import { classicMain } from './helpers.js'
+import { classicMain } from './m09-helpers.js'
 
 // A fake platform: records every call and lets the test fire events by hand.
 const fakePlatform = (seed = 42) => {