fix: hide cmhub curl download window

tests/test_ai.py

@@ -725,12 +725,15 @@ class AITests(TempDirMixin, unittest.TestCase):
             self.assertIn("--noproxy", args)
             self.assertEqual("*", args[args.index("--noproxy") + 1])
             self.assertFalse(kwargs["shell"])
+            self.assertEqual(0x08000000, kwargs["creationflags"])
             output_path = args[args.index("--output") + 1]
             with open(output_path, "wb") as fh:
                 fh.write(generated_png)
             return SimpleNamespace(returncode=0, stdout=b"", stderr=b"")
 
-        with mock.patch("app.ai._find_system_curl", return_value=r"C:\Windows\System32\curl.exe"), \
+        with mock.patch("app.ai.os.name", "nt"), \
+                mock.patch("app.ai.subprocess.CREATE_NO_WINDOW", 0x08000000, create=True), \
+                mock.patch("app.ai._find_system_curl", return_value=r"C:\Windows\System32\curl.exe"), \
                 mock.patch("app.ai.subprocess.run", side_effect=fake_run), \
                 mock.patch("app.ai.socket.getaddrinfo", return_value=public_dns):
             image_bytes = ai._download_cmhub_image(
@@ -744,6 +747,17 @@ class AITests(TempDirMixin, unittest.TestCase):
         self.assertEqual(generated_png, image_bytes)
         self.assertEqual(1, len(calls))
 
+    def test_cmhub_curl_hidden_window_kwargs_are_windows_only(self):
+        with mock.patch("app.ai.os.name", "nt"), \
+                mock.patch("app.ai.subprocess.CREATE_NO_WINDOW", 0x08000000, create=True):
+            self.assertEqual(
+                {"creationflags": 0x08000000},
+                ai._subprocess_hidden_window_kwargs(),
+            )
+
+        with mock.patch("app.ai.os.name", "posix"):
+            self.assertEqual({}, ai._subprocess_hidden_window_kwargs())
+
     def test_cmhub_image_download_skips_curl_for_private_url(self):
         with mock.patch("app.ai._find_system_curl", return_value=r"C:\Windows\System32\curl.exe"), \
                 mock.patch("app.ai.subprocess.run") as run: