fix: add type parameters for generic list in memory tests

Fixes mypy [type-arg] errors in test_memory_node.py.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: mjnovice

tests/agent/react/test_memory_node.py

@@ -142,7 +142,7 @@ def memory_config(self):
         return MemoryConfig(memory_space_id="test-space-id")
 
     def test_graph_has_memory_recall_node(
-        self, mock_model: MagicMock, messages: list, memory_config: MemoryConfig
+        self, mock_model: MagicMock, messages: list[SystemMessage], memory_config: MemoryConfig
     ) -> None:
         result: StateGraph[Any] = create_agent(
             mock_model, [], messages, memory=memory_config
@@ -151,7 +151,7 @@ def test_graph_has_memory_recall_node(
         assert AgentGraphNode.MEMORY_RECALL in graph.nodes
 
     def test_graph_edges_with_memory(
-        self, mock_model: MagicMock, messages: list, memory_config: MemoryConfig
+        self, mock_model: MagicMock, messages: list[SystemMessage], memory_config: MemoryConfig
     ) -> None:
         result: StateGraph[Any] = create_agent(
             mock_model, [], messages, memory=memory_config
@@ -163,7 +163,7 @@ def test_graph_edges_with_memory(
         assert Edge("__start__", AgentGraphNode.INIT) not in graph.edges
 
     def test_graph_without_memory_has_no_recall_node(
-        self, mock_model: MagicMock, messages: list
+        self, mock_model: MagicMock, messages: list[SystemMessage]
     ) -> None:
         result: StateGraph[Any] = create_agent(mock_model, [], messages)
         graph = result.compile().get_graph()