Bug report : Snapshot archive uses backslash as path separator on Windows, causing directory structure loss when extracting on Linux #132

Describe the bug
I was using the fabric mod to create a snapshot backup on my Windows computer, and then migrate the entire server to a Ubuntu server. After restoring it using the mod's CLI mode or the standard unzip command, all files are extracted with a backslash '\' in their filenames, and no directory structure is preserved.

I suspect why this happens is that the ZIP file stores entry paths using Windows-style backslashes. Tools on Linux treat the backslash as a literal character in the filename, so they do not create the intended nested directories.

To Reproduce
Steps to reproduce the behavior:

1. Host a fabric server with this mod installed on Windows machine.
2. Run /backup snapshot in-game or in console to create a snapshot backup.
3. Transfer the entire fabric server to a Ubuntu machine.
4. Use command java -jar ../mods/AdvancedBackups-fabric-1.21.2-3.7.1.jar, and follow instructions to restore the snapshot file created.
5. Observe that all files appear in the world directory with '\' in their names, instead of being organized into folders.

Expected behavior
The ZIP archive should store paths using forward slashes '/', so that when extracted on Linux (and other Unix-like systems), the directory hierarchy is correctly recreated.

Screenshots

Versioning (please complete the following information):

• OS: Windows 11 -> Ubuntu 24.04.4
• Minecraft Version(s): 1.21.4
• Modloader(s): Fabric
• Mod Version: 3.7.1

Additional context
N-A