feat: 增强 core/agents 工具和 API

- 新增 loop.py Agent 运行循环
- 优化 memory.py 记忆模块
- 扩展 api/routes.py 接口
- 更新 tools 模块：builtin.py, manager.py, __init__.py
- 新增 .env.example 配置示例
- 更新 requirements.txt 依赖

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

core/agents/agent/loop.py

@@ -79,6 +79,18 @@ class AgentLoop:
         """
         history = history or []
 
+        # Load history from session if session_key is provided
+        if session_key and session_key != "default":
+            loaded_history = self.memory.get_history(session_key, max_messages=20)
+            if loaded_history:
+                logger.info(f"Loaded {len(loaded_history)} messages from session history")
+                # Merge loaded history with provided history (loaded takes precedence if empty)
+                if not history:
+                    history = loaded_history
+                else:
+                    # Append loaded history before current messages
+                    history = loaded_history + history
+
         # Check if dynamic provider parameters are provided
         if api_key or model_provider:
             logger.info(f"Using dynamic provider: model_provider={model_provider}, model_name={model_name}, base_url={base_url}")
@@ -142,6 +154,19 @@ class AgentLoop:
             Agent response content
         """
         history = history or []
+
+        # Load history from session if session_key is provided
+        if session_key and session_key != "default":
+            loaded_history = self.memory.get_history(session_key, max_messages=20)
+            if loaded_history:
+                logger.info(f"Loaded {len(loaded_history)} messages from session history")
+                # Merge loaded history with provided history (loaded takes precedence if empty)
+                if not history:
+                    history = loaded_history
+                else:
+                    # Append loaded history before current messages
+                    history = loaded_history + history
+
         provider = provider or self.provider
         model = model or self.model
 
@@ -191,6 +216,18 @@ class AgentLoop:
         """
         history = history or []
 
+        # Load history from session if session_key is provided
+        if session_key and session_key != "default":
+            loaded_history = self.memory.get_history(session_key, max_messages=20)
+            if loaded_history:
+                logger.info(f"[stream] Loaded {len(loaded_history)} messages from session history")
+                # Merge loaded history with provided history (loaded takes precedence if empty)
+                if not history:
+                    history = loaded_history
+                else:
+                    # Append loaded history before current messages
+                    history = loaded_history + history
+
         # Check if dynamic provider parameters are provided
         if api_key or model_provider:
             logger.info(f"[stream] Using dynamic provider: model_provider={model_provider}, model_name={model_name}, base_url={base_url}")
@@ -244,6 +281,19 @@ class AgentLoop:
             Response content chunks
         """
         history = history or []
+
+        # Load history from session if session_key is provided
+        if session_key and session_key != "default":
+            loaded_history = self.memory.get_history(session_key, max_messages=20)
+            if loaded_history:
+                logger.info(f"[stream] Loaded {len(loaded_history)} messages from session history")
+                # Merge loaded history with provided history (loaded takes precedence if empty)
+                if not history:
+                    history = loaded_history
+                else:
+                    # Append loaded history before current messages
+                    history = loaded_history + history
+
         provider = provider or self.provider
         model = model or self.model
 
@@ -461,3 +511,19 @@ class AgentLoop:
                 self.memory.add_to_history("user", str(content)[:1000], session_key)
             elif role == "assistant" and content:
                 self.memory.add_to_history("assistant", str(content)[:1000], session_key)
+            # Save tool_calls for assistant messages (needed for multi-turn tool calls)
+            elif role == "assistant" and 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)
+            elif role == "tool":
+                tool_call_id = m.get("tool_call_id", "")
+                tool_name = m.get("name", "")
+                tool_content = m.get("content", "")
+                tool_result_str = json.dumps({
+                    "tool_call_id": tool_call_id,
+                    "name": tool_name,
+                    "content": tool_content
+                })
+                self.memory.add_to_history("tool", f"[tool_result]{tool_result_str}", session_key)