test(packaging): pin bash on the nightly version step

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tools/packaging/configure-linux-frame-copy-build.test.mjs

@@ -479,6 +479,15 @@ test('keeps non-Linux builds independent from the Linux runtime prerequisite', (
     );
     assert.equal(linuxJob.strategy['fail-fast'], false);
     assert.deepEqual(linuxJob.steps, crossPlatformJob.steps);
+    // Windows runners default to PowerShell, where the bash-style
+    // "${NIGHTLY_VERSION}" expands to nothing and the version script rejects
+    // the empty value; the step must pin bash on every host.
+    const applyNightlyVersion = crossPlatformJob.steps.find(
+        (step) => step.name === 'Apply nightly version'
+    );
+    assert.ok(applyNightlyVersion);
+    assert.equal(applyNightlyVersion.shell, 'bash');
+    assert.match(applyNightlyVersion.run, /--version "\$\{NIGHTLY_VERSION\}"/);
     assert.deepEqual(buildWorkflowConfig.jobs['create-release'].needs, [
         'nightly-version',
         'build-cross-platform',