refactor(memory): Memory V2 P3 - 舍弃后台抽取 + Gateway 端点收口

P3 在 P1/P2 基础上完成 Memory V2 收尾:

舍弃后台抽取:
- 删除 updater/queue/storage/prompt/summarization_hook 五个模块
- 移除 background_extraction 配置段、扁平字段兼容、storage 字段
- 理由:Hindsight auto_retain 已自动留存每轮对话,后台抽取冗余

Hindsight 召回注入改用 wrap_model_call:
- 由 before_model 改为 wrap_model_call —— 召回只注入单次模型请求、
  不落持久 state,从根上消除 <memory-context> 泄漏给前端的风险
- builtin frozen snapshot 仍走系统提示词

Gateway 端点收口为 /api/memory/v2*:
- 删除旧 facts/history 端点 (/api/memory、/memory/facts 等)
- 新增 entries 增删改 (POST/PUT/DELETE /memory/v2/entries)
- 新增 POST /memory/v2/search —— Hindsight recall/reflect 检索代理
- client.py memory 方法重写为 V2 等价方法

文档同步更新 CLAUDE.md 与 MEMORY_V2_DESIGN_ZH.md。

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

offline-backend-20260512/backend/packages/harness/deerflow/agents/lead_agent/agent.py

@@ -5,12 +5,11 @@ from langchain.agents.middleware import AgentMiddleware
 from langchain_core.runnables import RunnableConfig
 
 from deerflow.agents.lead_agent.prompt import apply_prompt_template
-from deerflow.agents.memory.summarization_hook import memory_flush_hook
 from deerflow.agents.middlewares.clarification_middleware import ClarificationMiddleware
 from deerflow.agents.middlewares.loop_detection_middleware import LoopDetectionMiddleware
-from deerflow.agents.middlewares.memory_middleware import MemoryMiddleware
-from deerflow.agents.middlewares.setup_agent_approval_middleware import SetupAgentApprovalMiddleware
-from deerflow.agents.middlewares.subagent_limit_middleware import SubagentLimitMiddleware
+from deerflow.agents.middlewares.memory_middleware import MemoryMiddleware
+from deerflow.agents.middlewares.setup_agent_approval_middleware import SetupAgentApprovalMiddleware
+from deerflow.agents.middlewares.subagent_limit_middleware import SubagentLimitMiddleware
 from deerflow.agents.middlewares.summarization_middleware import BeforeSummarizationHook, DeerFlowSummarizationMiddleware
 from deerflow.agents.middlewares.title_middleware import TitleMiddleware
 from deerflow.agents.middlewares.todo_middleware import TodoMiddleware
@@ -91,9 +90,8 @@ def _create_summarization_middleware(*, app_config: AppConfig | None = None) ->
     if config.summary_prompt is not None:
         kwargs["summary_prompt"] = config.summary_prompt
 
+    # Memory V2:不再有后台抽取队列,无需 summarization 前的 flush hook。
     hooks: list[BeforeSummarizationHook] = []
-    if resolved_app_config.memory.enabled:
-        hooks.append(memory_flush_hook)
 
     # The logic below relies on two assumptions holding true: this factory is
     # the sole entry point for DeerFlowSummarizationMiddleware, and the runtime
@@ -304,10 +302,10 @@ def _build_middlewares(
     if custom_middlewares:
         middlewares.extend(custom_middlewares)
 
-    middlewares.append(SetupAgentApprovalMiddleware())
-
-    # ClarificationMiddleware should always be last
-    middlewares.append(ClarificationMiddleware())
+    middlewares.append(SetupAgentApprovalMiddleware())
+
+    # ClarificationMiddleware should always be last
+    middlewares.append(ClarificationMiddleware())
     return middlewares