feat: add style presets, multi-language support and ISO2-based mass upload

[Ryan-Carloso]

This PR introduces support for additional languages and style presets.

It also adds a mass upload feature that requires assets to be organized by ISO2 language folders, ensuring consistent mapping between languages and uploaded files.

[BlackMac]

I love all of the changes, just some small remarks:

• Making image format a setting in preferences rather than a choice on each export
• Themes are definitely a better solution than the current "Copy Style from..." and "Apply Style to all..." system. If we go this route, I'd suggest removing those two options and keeping the name "Style" consistently (the button says "Style" but the menu title says "Theme").

[Ryan-Carloso]

Thanks for the feedback!
Changes are already applied.
Happy to iterate further if needed.