fix：裁切缓存，删除超时聊天流，修复内存溢出问题

src/chat/heart_flow/heartflow_manager.py

@@ -1,31 +1,39 @@
-import asyncio
-import traceback
-
+from collections import OrderedDict
 from typing import Dict
 
+import asyncio
+import time
+import traceback
+
 from src.chat.message_receive.chat_manager import chat_manager
 from src.common.logger import get_logger
 from src.maisaka.runtime import MaisakaHeartFlowChatting
 
 logger = get_logger("heartflow")
 
+HEARTFLOW_ACTIVE_RETENTION_SECONDS = 24 * 60 * 60
+HEARTFLOW_MAX_ACTIVE_CHATS = 100
+
 
 class HeartflowManager:
     """管理 session 级别的 Maisaka 心流实例。"""
 
     def __init__(self) -> None:
-        self.heartflow_chat_list: Dict[str, MaisakaHeartFlowChatting] = {}
+        self.heartflow_chat_list: OrderedDict[str, MaisakaHeartFlowChatting] = OrderedDict()
         self._chat_create_locks: Dict[str, asyncio.Lock] = {}
+        self._chat_last_active_at: Dict[str, float] = {}
 
     async def get_or_create_heartflow_chat(self, session_id: str) -> MaisakaHeartFlowChatting:
         """获取或创建指定会话对应的 Maisaka runtime。"""
         try:
             if chat := self.heartflow_chat_list.get(session_id):
+                self._touch_chat(session_id)
                 return chat
 
             create_lock = self._chat_create_locks.setdefault(session_id, asyncio.Lock())
             async with create_lock:
                 if chat := self.heartflow_chat_list.get(session_id):
+                    self._touch_chat(session_id)
                     return chat
 
                 chat_session = chat_manager.get_session_by_session_id(session_id)
@@ -35,16 +43,59 @@ class HeartflowManager:
                 new_chat = MaisakaHeartFlowChatting(session_id=session_id)
                 await new_chat.start()
                 self.heartflow_chat_list[session_id] = new_chat
+                self._touch_chat(session_id)
+                await self._evict_over_limit_chats(protected_session_id=session_id)
                 return new_chat
         except Exception as exc:
             logger.error(f"创建心流聊天 {session_id} 失败: {exc}", exc_info=True)
             traceback.print_exc()
             raise
 
+    def _touch_chat(self, session_id: str) -> None:
+        """记录会话最近活跃时间，并维护心流实例的 LRU 顺序。"""
+        self._chat_last_active_at[session_id] = time.time()
+        self.heartflow_chat_list.move_to_end(session_id)
+
+    async def _evict_over_limit_chats(self, *, protected_session_id: str) -> None:
+        """当实例数量超过上限时，仅淘汰 24 小时内无消息的旧会话。"""
+        while len(self.heartflow_chat_list) > HEARTFLOW_MAX_ACTIVE_CHATS:
+            session_id = self._find_evictable_session_id(protected_session_id=protected_session_id)
+            if session_id is None:
+                return
+            await self._evict_chat(session_id, reason="cache_limit")
+
+    def _find_evictable_session_id(self, *, protected_session_id: str) -> str | None:
+        """按 LRU 查找超过活跃保护窗口的可淘汰会话。"""
+        expire_before = time.time() - HEARTFLOW_ACTIVE_RETENTION_SECONDS
+        for session_id in self.heartflow_chat_list:
+            if session_id == protected_session_id:
+                continue
+            last_active_at = self._chat_last_active_at.get(session_id, 0.0)
+            if last_active_at <= expire_before:
+                return session_id
+        return None
+
+    async def _evict_chat(self, session_id: str, *, reason: str) -> None:
+        """停止并移除指定会话的心流实例。"""
+        chat = self.heartflow_chat_list.pop(session_id, None)
+        self._chat_last_active_at.pop(session_id, None)
+        lock = self._chat_create_locks.get(session_id)
+        if lock is not None and not lock.locked():
+            self._chat_create_locks.pop(session_id, None)
+        if chat is None:
+            return
+
+        try:
+            await chat.stop()
+            logger.info(f"已淘汰心流聊天 {session_id}: reason={reason}")
+        except Exception as exc:
+            logger.warning(f"淘汰心流聊天 {session_id} 失败: {exc}", exc_info=True)
+
     def adjust_talk_frequency(self, session_id: str, frequency: float) -> None:
         """调整指定聊天流的说话频率。"""
         chat = self.heartflow_chat_list.get(session_id)
         if chat:
+            self._touch_chat(session_id)
             chat.adjust_talk_frequency(frequency)
             logger.info(f"已调整聊天 {session_id} 的说话频率为 {frequency}")
         else: