fix(qa): run the macOS-only gates on Windows and Linux (#1061)

Seven QA scripts hard-coded macOS Google Chrome. They now share chromeExecutablePath(): PUPPETEER_EXECUTABLE_PATH when set, then macOS Chrome when installed, otherwise Puppeteer's managed browser. The cables screenshot path is built with fileURLToPath so it works on Windows. qa-overlay-baseline keeps its fixed Chrome because its baselines record the executable.

Co-authored-by: Sameh Khamis <[email protected]>

src/qaChrome.test.mjs

@@ -0,0 +1,27 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { MACOS_CHROME, chromeExecutablePath } from '../scripts/qa-chrome.mjs';
+
+test('gates keep macOS Chrome where it is installed', () => {
+  assert.equal(
+    chromeExecutablePath({ env: {}, exists: (p) => p === MACOS_CHROME }),
+    MACOS_CHROME,
+  );
+});
+
+test('gates fall back to Puppeteer’s browser without macOS Chrome', () => {
+  assert.equal(
+    chromeExecutablePath({ env: {}, exists: () => false }),
+    undefined,
+  );
+});
+
+test('an explicit executable path wins', () => {
+  assert.equal(
+    chromeExecutablePath({
+      env: { PUPPETEER_EXECUTABLE_PATH: 'C:\\Chrome\\chrome.exe' },
+      exists: () => true,
+    }),
+    'C:\\Chrome\\chrome.exe',
+  );
+});