fix: handle malformed JSON payloads in worker with error logging

backend/tests/test_jobs.py

@@ -171,3 +171,20 @@ class TestRandomNumberJobHandler:
 
         # Should not have called execute
         mock_conn.execute.assert_not_called()
+
+    @pytest.mark.asyncio
+    async def test_malformed_json_payload_does_not_insert(self):
+        """Verify no insert happens with malformed JSON payload."""
+        from worker import process_random_number_job
+
+        job = MagicMock()
+        job.id = 123
+        job.payload = b"not valid json {"
+
+        mock_conn = AsyncMock()
+        mock_pool = create_mock_pool(mock_conn)
+
+        await process_random_number_job(job, mock_pool)
+
+        # Should not have called execute
+        mock_conn.execute.assert_not_called()