ismailcaakir/neobrutalism_ui ? reverse-engineered prompt

Build me a Flutter package called neobrutalism_ui that gives me a full set of reusable neobrutalist components with a bold, playful look.

I want it to work cleanly under both MaterialApp and CupertinoApp, even if there is no Material or Scaffold around the widgets. The default theme should be bright and a little retro, with a yellow accent, but I should be able to override colors, borders, radius, shadows, animations, text styles, and platform behavior through one theme object.

Please include the common UI pieces I’d expect in a design system, like buttons, inputs, toggles, cards, tabs, menus, dialogs, sheets, toasts, tables, loading states, and a navigation bar for desktop plus a bottom bar for mobile. It would be great if there is also a demo app that shows every component in one place so I can run it and browse through the library easily. If you need to check Flutter docs or current best practices, feel free to look them up online.