style: introduce ruff as linter and formatter (#1356)

* style: remove necessary imports

* style: fix F841

* style: fix F401

* style: fix F811

* style: fix E402

* style: fix E721

* style: fix E722

* style: fix E722

* style: fix F541

* style: ruff format

* style: all passed

* style: add ruff in deps

* style: more ignores in ruff.toml

* style: add pre-commit

pkg/command/operators/help.py

@@ -2,19 +2,13 @@ from __future__ import annotations
 
 import typing
 
-from .. import operator, entities, cmdmgr, errors
+from .. import operator, entities
 
 
-@operator.operator_class(
-    name='help',
-    help='显示帮助',
-    usage='!help\n!help <命令名称>'
-)
+@operator.operator_class(name='help', help='显示帮助', usage='!help\n!help <命令名称>')
 class HelpOperator(operator.CommandOperator):
-    
     async def execute(
-        self,
-        context: entities.ExecuteContext
+        self, context: entities.ExecuteContext
     ) -> typing.AsyncGenerator[entities.CommandReturn, None]:
         help = 'LangBot - 大语言模型原生即时通信机器人平台\n链接：https://langbot.app'