fix(memory): use explicit function name in tool_choice for DashScope compatibility

nanobot/agent/memory.py

@@ -112,15 +112,17 @@ class MemoryStore:
 ## Conversation to Process
 {self._format_messages(messages)}"""
 
-        try:
-            response = await provider.chat_with_retry(
-                messages=[
+        chat_messages = [
             {"role": "system", "content": "You are a memory consolidation agent. Call the save_memory tool with your consolidation of the conversation."},
             {"role": "user", "content": prompt},
-                ],
+        ]
+
+        try:
+            response = await provider.chat_with_retry(
+                messages=chat_messages,
                 tools=_SAVE_MEMORY_TOOL,
                 model=model,
-                tool_choice="required",
+                tool_choice={"type": "function", "function": {"name": "save_memory"}},
             )
 
             if not response.has_tool_calls: