fix: stop panel description churn

tests/test_account_linking_panel.py

@@ -74,7 +74,7 @@ class AccountLinkingPanelTests(unittest.IsolatedAsyncioTestCase):
         self.assertTrue(result)
         panel_service.update_user_details_on_panel.assert_awaited_once()
         _, payload = panel_service.update_user_details_on_panel.await_args.args[:2]
-        self.assertEqual(payload["description"], "alice")
+        self.assertNotIn("description", payload)
         self.assertEqual(payload["email"], "linked@example.com")
 
     def test_panel_description_for_user_excludes_email(self):
@@ -87,6 +87,16 @@ class AccountLinkingPanelTests(unittest.IsolatedAsyncioTestCase):
 
         self.assertEqual(_panel_description_for_user(user), "alice\nAlice")
 
+    def test_panel_description_for_user_filters_broken_lines(self):
+        user = SimpleNamespace(
+            email="linked@example.com",
+            username="alice??",
+            first_name="????",
+            last_name="Smith",
+        )
+
+        self.assertEqual(_panel_description_for_user(user), "alice??\nSmith")
+
     async def test_merged_panel_identity_deletes_source_before_updating_target(self):
         calls = []