更好的缓存，扬掉global，重构代码，整理聊天逻辑 (#16)

* 实现缓存装饰器，优化数据获取和存储逻辑

* 重构代码，准备将聊天请求逻辑移入MarshoHandler

* 记录点（

* unfinished

* 🎨 重写基本完毕

* 移除未使用import，添加漏掉的换行

nonebot_plugin_marshoai/plugin/func_call/models.py

@@ -19,7 +19,7 @@ class SessionContext(BaseModel):
     bot: Bot
     event: Event
     matcher: Matcher
-    state: T_State
+    # state: T_State
     caller: Any = None
 
     class Config:
@@ -30,5 +30,5 @@ class SessionContextDepends(BaseModel):
     bot: str | None = None
     event: str | None = None
     matcher: str | None = None
-    state: str | None = None
+    # state: str | None = None
     caller: str | None = None