utils/hi_selection_area library

1. chat_message package
2. documentation
3. utils/hi_selection_area.dart

chat_message package

1. Libraries
2. chat_message
3. core/chat_controller
4. models/message_model
5. utils/hi_dialog
6. utils/hi_selection_area
7. utils/hi_utils
8. utils/wechat_data_format
9. widget/chat_list
10. widget/default_message_widget