kun-codes/Koncentro ? reverse-engineered prompt

Build me a cross platform desktop productivity app that helps me stay focused while I work.

I want it to combine a Pomodoro timer, a simple task list, and a website blocker in one clean app. The idea is that I can add tasks, set time limits for them, start focus sessions, and block distracting sites while I’m working. It should also support separate workspaces, so I can keep different settings and task lists for work and personal projects.

Please make the UI feel polished and modern, with a Fluent style look, and make it work on Windows, macOS, and Linux. Include basic settings for timer behavior and website blocking, and make the blocker work with either a blocklist or an allowlist. If you need to look up current docs online while building it, go ahead.