Add comprehensive documentation for SnapForm features and workflows

- Introduced new guides for Depth Plane, Surface, and animation workflows.
- Added installation instructions and FAQs to assist users in setup and troubleshooting.
- Created a quick-start guide for first-time users to convert images to Depth Planes.
- Documented the process for removing backgrounds from images.
- Established a models and storage section to clarify data management.
- Included a stylesheets file for improved documentation styling.
- Updated mkdocs configuration for better navigation and theme settings.

docs/outputs.md

@@ -1,5 +1,8 @@
 # 输出格式
 
+本页说明任务文件的字段与序列化约定，主要用于开发与数据检查。普通使用者只需了解
+[模型、设备与存储](models-and-storage.md)中的 Job 文件夹说明。
+
 ## Debug
 
 Debug 用于直接比较 DA3、MoGe-2 与 BEN2 模型 API 的返回效果，不复用 Depth、Surface 或 Geometry