feat(subscription): add membership access preflight

tests/test_appconfig.py

@@ -480,6 +480,29 @@ class AppConfigTests(TempDirMixin, unittest.TestCase):
 
         self.assert_removed(temp_dir)
 
+    def test_subscription_notice_id_persists_without_credentials(self):
+        with self.make_temp_dir() as temp_dir:
+            config_path = os.path.join(temp_dir, "config.json")
+
+            loaded = appconfig.load_config(config_path)
+            self.assertEqual("", appconfig.subscription_notice_id(loaded))
+
+            saved = appconfig.save_subscription_notice_id(
+                "subscription-notice-20260721",
+                path=config_path,
+            )
+            self.assertEqual(
+                "subscription-notice-20260721",
+                appconfig.subscription_notice_id(saved),
+            )
+            reloaded = appconfig.load_config(config_path)
+            self.assertEqual(
+                "subscription-notice-20260721",
+                appconfig.subscription_notice_id(reloaded),
+            )
+
+        self.assert_removed(temp_dir)
+
     def test_cmhub_base_url_normalizes_to_gateway_root(self):
         cases = {
             "https://cmhub.example.com/": "https://cmhub.example.com",