docs: remove outdated and unused documentation files

A significant number of documentation files, including design documents, user guides, and old images, have been removed to clean up the repository and eliminate outdated information. This reduces clutter and ensures that the documentation accurately reflects the current state of the project.

Key removals include:
- `memory_system_design_v3.md`
- `model_configuration_guide.md`
- `PERMISSION_SYSTEM.md`
- `CONTRIBUTE.md`
- `vector_db_usage_guide.md

docs/plugins/quick-start.md

@@ -90,7 +90,7 @@ class HelloWorldPlugin(BasePlugin):
 
 在日志中你应该能看到插件被加载的信息。虽然插件还没有任何功能，但它已经成功运行了！
 
-![1750326700269](image/quick-start/1750326700269.png)
+![1750326700269](../assets/1750326700269.png)
 
 ### 5. 添加第一个功能：问候Action
 
@@ -180,7 +180,7 @@ MoFox_Bot可能会选择使用你的问候Action，发送回复：
 嗨！很开心见到你！😊
 ```
 
-![1750332508760](image/quick-start/1750332508760.png)
+![1750332508760](../assets/1750332508760.png)
 
 > **💡 小提示**：MoFox_Bot会智能地决定什么时候使用它。如果没有立即看到效果，多试几次不同的消息。