Sharedasset detection using checksum can fail when switching between proton and native on second install [no fix needed?]

For some chapters (eg. ch8), installer chooses sharedassets depending on the checksum of the original sharedassets0.assets.

Because our installer overwrites the sharedassets0.assets file, we also check the checksum of the sharedassets0.assets.backup file to see the "original" sharedassets file. This .backup file is created by our installer when you install the mod.

However, if you:

- First install using say Proton, it will create a sharedassets0.assets.backup file from the Proton install.
- Switch back to Native. This will overwrite the sharedassets0.assets with the Native version
- Perform an install of the mod the first time, the install will work OK (it will overwrite the sharedassets0.assets with the mod version)
- Because a .backup file already exists, this install won't overwrite the sharedassets0.assets.backup file
- Now, when you perform the second install or update, the sharedassets0.assets will be the mod version, which the installer does not recognise. Also, the sharedassets0.assets.backup file is from the Proton install, which the mod also does not recognize. This will cause an install error.

查看安装程序的共享资源检测逻辑，很可能在处理校验和或资源管理的文件中。该问题描述了一个场景：来自 Proton 安装的备份文件 (sharedassets0.assets.backup) 在后续的 Native 安装上导致不匹配。首先找到为 sharedassets0.assets 及其备份计算校验和的位置。理解安装流程以查看备份是如何创建以及何时被覆盖的。测试涉及模拟在 Proton 和 Native 模式之间切换的安装。

由索引模型根据 Issue 内容生成。