fix: add space between authors && keywords

sorbobotapp/vector_store.py

@@ -272,8 +272,8 @@ class CustomVectorStore(VectorStore):
                         a.doi,
                         a.hal_id,
                         a.abstract_en,
-                        string_agg(distinct keyword."name", ',') as keywords, 
-                        string_agg(distinct author."name", ',') as authors,
+                        string_agg(distinct keyword."name", ', ') as keywords, 
+                        string_agg(distinct author."name", ', ') as authors,
                         abstract_embedding_en {self.distance_strategy} '{str(embedding)}' as distance
                     from article a
                     left join article_keyword ON article_keyword.article_id = a.id