Use dependency injection for health status and add health router regression test

backend/tests/test_routers/test_health.py

@@ -3,6 +3,8 @@
 import pytest
 from httpx import AsyncClient
 
+from app.models.server import ServerStatus
+
 
 @pytest.mark.asyncio
 async def test_health_check_returns_200(client: AsyncClient) -> None:
@@ -25,3 +27,14 @@ async def test_health_check_content_type_is_json(client: AsyncClient) -> None:
     """``GET /api/health`` must set the ``Content-Type`` header to JSON."""
     response = await client.get("/api/health")
     assert "application/json" in response.headers.get("content-type", "")
+
+
+@pytest.mark.asyncio
+async def test_health_check_respects_cached_server_status(client: AsyncClient) -> None:
+    """The health response should reflect the injected cached server status."""
+    client._transport.app.state.server_status = ServerStatus(online=True)
+
+    response = await client.get("/api/health")
+
+    assert response.status_code == 200
+    assert response.json()["fail2ban"] == "online"