Mixxx 2.5.4: enhanced controller mappings, improved library, and stability fixes

Mixxx 2.5.4 delivers updated controller mappings for Korg Kaoss DJ, Numark-NS6II, Pioneer DJ CDJ, Reloop Beatmix, and Traktor S4Mk3. This release also enhances library usability with better playlist handling and a functional Cancel button in the library scanner. The update also resolves various stability, audio, and UI issues and includes support for Qt 6.10, macOS Sequoia 15, and Ubuntu 26.04.