refactor: separate application UI state owners

src/data/detectionHost.test.mjs

@@ -1,3 +1,4 @@
+import { readShellSource } from '../testSupport/readShellSource.mjs';
 import test from 'node:test';
 import assert from 'node:assert/strict';
 import { readFileSync } from 'node:fs';
@@ -671,7 +672,7 @@ test('pathological detection paint holds alternate frames without freezing share
 
 test('detection cannot resurrect a private canvas, listener, matrix, resize, clear, or UI inventory', () => {
   const source = readFileSync(new URL('./detection.js', import.meta.url), 'utf8');
-  const uiSource = readFileSync(new URL('../ui/applicationShell.js', import.meta.url), 'utf8')
+  const uiSource = readShellSource()
   + '\n' + readFileSync(new URL('../ui/visualPresets.js', import.meta.url), 'utf8');
   assert.doesNotMatch(source, /createElement\(\s*['"]canvas['"]\s*\)/);
   assert.doesNotMatch(source, /postRender\.addEventListener/);