[功能] 多文件游戏的下载选项 (补丁、修改程序、ES-DE 结构)

Is your feature request related to a problem? Please describe.

RomM is excellent at organizing complex, multi-file games by recognizing "special folders" such as patch, hack, and translation. However, the current download functionality treats the entire game directory as a single unit, downloading everything into a ZIP archive. This is inefficient and lacks flexibility for several common use cases:

1. Redundant Data: A user wanting to play only the base game is forced to download all associated hacks, patches, and manuals, consuming unnecessary bandwidth.
2. Manual Patching Required: To play a patched version of a game, the user must download the entire folder, use an external tool (such as Lunar IPS) to apply the patch to a copy of the base ROM, and then manage this new file. This process is cumbersome and leads to storing duplicate, large ROM files.
3. Soft-patching with ES-DE: ES-DE supports "soft-patching," where a base ROM and a patch file are stored together inside a folder named after the base ROM. This allows RetroArch to automatically apply the patch when launching the game. RomM's current download method does not produce a structure compatible with this, forcing the user to create it manually.