Close Campaign interface audit gaps

tests/test_manifest_navigation.py

@@ -62,3 +62,12 @@ def test_aggregate_reports_are_an_integrated_campaign_view() -> None:
     ]
     assert len(report_surfaces) == 1
     assert report_surfaces[0].description == "/campaigns/reports"
+
+
+def test_reusable_template_library_is_not_owned_by_campaign() -> None:
+    manifest = get_manifest()
+    assert manifest.frontend is not None
+
+    assert "/templates" not in {item.path for item in manifest.nav_items}
+    assert "/templates" not in {item.path for item in manifest.frontend.nav_items}
+    assert "/templates" not in {route.path for route in manifest.frontend.routes}