Use namespace for graph_name before falling back to env or default value

- Update graph_name initialization
- Add namespace override support
- Maintain backward compatibility
- Prioritize namespace over env variable

lightrag/kg/postgres_impl.py

@@ -587,7 +587,7 @@ class PGGraphStorage(BaseGraphStorage):
         print("no preloading of graph with AGE in production")
 
     def __post_init__(self):
-        self.graph_name = os.environ.get("AGE_GRAPH_NAME", "lightrag")
+        self.graph_name = self.namespace or os.environ.get("AGE_GRAPH_NAME", "lightrag")
         self._node_embed_algorithms = {
             "node2vec": self._node2vec_embed,
         }