fix: 修复 AgentLoop 消息保存逻辑

- 同时保存 assistant 消息的 content 和 tool_calls
- 修复多轮工具调用场景下的消息丢失问题

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

core/agents/agent/loop.py

@@ -509,11 +509,12 @@ class AgentLoop:
 
             if role == "user" and content:
                 self.memory.add_to_history("user", str(content)[:1000], session_key)
-            elif role == "assistant" and content:
+            elif role == "assistant":
+                # Save assistant message content
+                if content:
                     self.memory.add_to_history("assistant", str(content)[:1000], session_key)
-            # Save tool_calls for assistant messages (needed for multi-turn tool calls)
+                # Save tool_calls if present (needed for multi-turn tool calls)
-            elif role == "assistant" and m.get("tool_calls"):
+                if m.get("tool_calls"):
-                # Save the assistant message with tool_calls
                     tool_calls_str = json.dumps(m.get("tool_calls", []))
                     self.memory.add_to_history("assistant", f"[tool_calls]{tool_calls_str}", session_key)
             # Save tool results (needed for multi-turn conversations)