amir1376/ab-download-manager ? reverse-engineered prompt

I want you to build me a desktop download manager app that's way more powerful than the standard ones in browsers. The key is to speed up downloads, probably by fetching multiple parts of a file simultaneously. It needs to have features for organizing downloads, like creating queues and scheduling them to run at specific times.

A crucial feature is integration with browsers like Chrome and Firefox, so it can automatically take over when I click a download link. The app should have a modern, clean user interface with multiple themes, including light and dark modes. Please build it using Kotlin so it's a cross-platform application that can run on Windows, Mac, and Linux. The final project should be free and open-source.