fix(#142): SL HTTP 5xx als Fehler raisen statt return []

Symptom: Monitoring-Scan zeigte bei SL seen=0 errors=OK, obwohl der
Umbraco-Backend HTTP 500 zurueckgab. Im _post_search wurde 5xx via
'logger.error + return []' geschluckt, sodass der Monitoring-Layer
die Fehlerursache nicht in monitoring_daily_summary persistierte.

Fix: bei resp.status_code != 200 httpx.HTTPStatusError raisen — das
propagiert durch search() ueber _search_adapter ins outer except in
daily_scan, das den Fehlertext in summary.errors schreibt.

Regression-Test test_search_propagates_http_500.

Closes #142

app/parlamente.py

@@ -3206,7 +3206,10 @@ class SaarlandAdapter(ParlamentAdapter):
             )
             if resp.status_code != 200:
                 logger.error("SL HTTP %s: %s", resp.status_code, resp.text[:200])
-                return []
+                raise httpx.HTTPStatusError(
+                    f"SL HTTP {resp.status_code}",
+                    request=resp.request, response=resp,
+                )
             data = resp.json()
             return data.get("FilteredResult", []) or []
         except Exception:

tests/test_parlamente.py

@@ -576,3 +576,27 @@ class TestSaarlandSearchPropagatesErrors:
 
         with pytest.raises(httpx.ConnectError):
             asyncio.run(_run())
+
+    def test_search_propagates_http_500(self):
+        """HTTP 5xx response must NOT be silently turned into empty results
+        (regression #142): a 500 from the Umbraco backend used to log+return
+        [], hiding it from the monitoring summary."""
+        import httpx
+        from app.parlamente import SaarlandAdapter
+
+        adapter = SaarlandAdapter()
+
+        async def _run():
+            mock_client = AsyncMock()
+            mock_client.__aenter__ = AsyncMock(return_value=mock_client)
+            mock_client.__aexit__ = AsyncMock(return_value=False)
+            mock_resp = MagicMock()
+            mock_resp.status_code = 500
+            mock_resp.text = "Server Error"
+            mock_resp.request = MagicMock()
+            mock_client.post = AsyncMock(return_value=mock_resp)
+            with patch.object(adapter, "_make_client", return_value=mock_client):
+                await adapter.search("Schule")
+
+        with pytest.raises(httpx.HTTPStatusError):
+            asyncio.run(_run())