microsoft/fluentui-system-icons ? reverse-engineered prompt

Build me a Fluent style icon library for an app ecosystem, with a big set of friendly, modern icons that can be used on Android, iPhone and iPad, Flutter, and as plain SVGs.

I want regular and filled versions, plus support for icons that need different left to right and right to left behavior. Make it easy to browse the full icon set, and include simple install and usage instructions for each platform. Also add a small demo app so people can open it and see the icons working right away.

If it helps, look up current docs online for the platform packaging details, but keep the result simple and practical. I care most about the icons being easy to ship, easy to update from the source assets, and nice to use in real apps.