fix(tests): correct skin engine test API call

The salvaged regression test called skin.get_spinner_list() which
doesn't exist on SkinConfig. Replace with direct dict access on
skin.spinner — same intent (verify default empty spinner is preserved
when user override is invalid).

tests/hermes_cli/test_skin_engine.py

@@ -226,7 +226,7 @@ class TestUserSkins:
         assert skin.name == "broken"
         assert skin.get_color("banner_title") == "#FFD700"
         assert skin.get_branding("agent_name") == "Hermes Agent"
-        assert skin.get_spinner_list("waiting_faces") == []
+        assert skin.spinner.get("waiting_faces", []) == []
         assert skin.tool_emojis == {}
         assert skin.tool_prefix == "!"