refactor: separate application UI state owners

src/cctvFocusPolicy.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';
@@ -73,7 +74,7 @@ test('CCTV enable retains a pre-await tracking snapshot when tracking clears dur
   assert.match(diagnostics[0][0], /before setEnabled await/);
   assert.match(diagnostics[1][0], /after setEnabled await/);
 
-  const uiSource = readFileSync(new URL('./ui/applicationShell.js', import.meta.url), 'utf8');
+  const uiSource = readShellSource();
   assert.match(uiSource, /await runCctvLayerEnableTransition\(\{/);
 });
 
@@ -114,6 +115,6 @@ test('a disposed UI cannot activate a camera when enabling finishes late', async
   release();
   await pending;
   assert.equal(activations, 0);
-  const uiSource = readFileSync(new URL('./ui/applicationShell.js', import.meta.url), 'utf8');
+  const uiSource = readShellSource();
   assert.match(uiSource, /shouldFocus: \(\) =>\s*!this\._disposed\s*&&\s*this\._dataManager\.isEnabled\('cctv'\)/);
 });