Refactor service status response: migrate bangui_version into version field

backend/tests/test_regression_500s.py

@@ -221,8 +221,8 @@ class TestFilterConfigImports:
 
 
 class TestServiceStatusBanguiVersion:
-    """Bug 4: ``get_service_status`` must include ``bangui_version``
-    in the ``ServiceStatusResponse`` it returns."""
+    """Bug 4: ``get_service_status`` must include application version
+    in the ``version`` field of the ``ServiceStatusResponse``."""
 
     async def test_online_response_contains_bangui_version(self) -> None:
         """The returned model must contain the ``bangui_version`` field."""
@@ -256,11 +256,9 @@ class TestServiceStatusBanguiVersion:
                 probe_fn=AsyncMock(return_value=online_status),
             )
 
-        assert hasattr(result, "bangui_version"), (
-            "ServiceStatusResponse is missing bangui_version — "
-            "Pydantic will raise ValidationError → 500"
+        assert result.version == app.__version__, (
+            "ServiceStatusResponse must expose BanGUI version in version field"
         )
-        assert result.bangui_version == app.__version__
 
     async def test_offline_response_contains_bangui_version(self) -> None:
         """Even when fail2ban is offline, ``bangui_version`` must be present."""
@@ -275,4 +273,4 @@ class TestServiceStatusBanguiVersion:
             probe_fn=AsyncMock(return_value=offline_status),
         )
 
-        assert result.bangui_version == app.__version__
+        assert result.version == app.__version__