Fix code review issues

- Use specific exception types instead of bare except
- Fix misleading comments about directory levels
- Remove redundant existence check before makedirs with exist_ok=True
- Use context manager for file opening to ensure proper cleanup

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

langbot/__main__.py

@@ -86,10 +86,7 @@ def main():
     # Set up the working directory
     # When installed as a package, we need to handle the working directory differently
     # We'll create data directory in current working directory if not exists
-    if not os.path.exists('data'):
-        print('Creating data directory in current working directory...')
-        print('在当前工作目录创建 data 目录...')
-        os.makedirs('data', exist_ok=True)
+    os.makedirs('data', exist_ok=True)
 
     loop = asyncio.new_event_loop()