fix: type the health test mode, pace cards with the stream, and size the results panel

backend/tests/test_health.py

@@ -5,7 +5,7 @@ from unittest.mock import AsyncMock, Mock
 import pytest
 from fastapi.testclient import TestClient
 
-from app.config import Settings
+from app.config import AppMode, Settings
 from app.main import create_app
 
 
@@ -23,7 +23,7 @@ def test_anthropic_client_uses_configured_timeout(monkeypatch: pytest.MonkeyPatc
     monkeypatch.setattr("app.main.AsyncAnthropic", constructor)
 
     live_settings = Settings(
-        app_mode="live",
+        app_mode=AppMode.LIVE,
         spotify_client_id="client-id",
         anthropic_api_key="api-key",
         llm_timeout_seconds=42.0,