test(qa): report-dir accepts Windows' ENOENT for a non-directory .gstack

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

changelog.d/gsta258-l3-windows-subset-reds.md

@@ -0,0 +1 @@
+**The Windows-safe test subset is green again on current main.** `test/qa-report-dir.test.ts` expected `ENOTDIR` when `.gstack` is a file, but Windows reports `ENOENT` for the same mistake, so the test failed on every Windows run (windows-free-tests run 41607809007 at f6d6215). The test now accepts either code on Windows and still requires `ENOTDIR` everywhere else. With Windows checks now running by path, a red subset test would block any pull request that touches it.

test/qa-report-dir.test.ts

@@ -84,7 +84,7 @@ test('report-dir names the filesystem cause when .gstack is not a directory', ()
   fs.writeFileSync(path.join(f.root, '.gstack'), 'not a directory\n');
   const r = f.tool('gstack-qa-evidence', 'report-dir');
   expect(r.status).toBe(2);
-  expect(r.stderr).toContain('report-dir failed: ENOTDIR');
+  expect(r.stderr).toMatch(process.platform === 'win32' ? /report-dir failed: (ENOTDIR|ENOENT)/ : /report-dir failed: ENOTDIR/);
 });
 
 test('report-dir refuses outside a git work tree instead of guessing a location', () => {