Avalonia/.NET 10 Port: Consolidated Windows/macOS/Linux support

[tzarc]

Description

Replaces the Windows WinForms and macOS Swift applications with a single Avalonia/.NET 10 codebase targeting Linux (x64, arm64), macOS (universal), and Windows (x64).

Raising for visibility. This is a very considerable PR, given the complete rewrite.

Non-maintainers: Don't expect merge any time soon.

Prebuilt binaries can be found on my fork's releases: https://github.com/tzarc/qmk_toolbox/releases/tag/beta-xplat

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Removed:

• windows/ WinForms C# application
• macos/ Swift/Xcode application

New application structure (src/):

• QmkToolbox.Core: platform-agnostic bootloader detection, flash/reset/EEPROM operations, USB device model, and service interfaces
• QmkToolbox.Desktop: Avalonia UI with MVVM (CommunityToolkit.Mvvm), HID console, key tester, settings, and platform service implementations
• QmkToolbox.Tests: xUnit test suite covering bootloader factory, flash commands, USB device parsing, settings serialisation, and resource layout

Flash tool changes:

• Binaries sourced from qmk_flashutils releases and bundled per-platform under resources/flashutils/{linux-x64,linux-arm64,osx,win-x64}/
• Added picotool (RP2040/RP2350) and wb32-dfu-updater_cli (WB32) — not present in the old platform-specific bundles
• Per-platform flashutils_release_* manifest files used for version-gated extraction; stale installs are wiped and re-extracted on version change

HID / hidapi:

• libhidapi bundled per-platform under resources/hidapi/ from qmk_hidapi releases; loaded at runtime via NativeLibrary rather than P/Invoke paths
• HidConsoleDevice and HidApiListener replace the platform-specific HID listeners in the old Windows/macOS codebases

Platform services:

• Linux: udev rules (50-qmk.rules) and qmk_id helper sourced from qmk_udev releases and extracted to /etc/udev/rules.d at runtime via UdevInstaller
• Windows: driver installation preserved via embedded qmk_driver_installer
• macOS/Linux USB hotplug via Usb.Events (wraps IOKit/udev per-platform)
• Windows USB hotplug rewritten to directly register for device notifications, bypassing WMI (Usb.Events supports Windows, but still uses WMI and is slow)
• Serial port resolution via DesktopSerialPortService (Registry lookup on Windows, /dev/serial/by-id on Linux, /dev/cu.* nodes on macOS)

Build and release:

• scripts/fetch-tools.sh downloads qmk_flashutils, qmk_hidapi, qmk_driver_installer, and qmk_udev from their respective GitHub releases into resources/
• scripts/publish-all.sh produces self-contained per-platform binaries
• scripts/make-app.sh / make-pkg-macos.sh / make-installer-win.sh package platform-specific installers
• GitHub Actions CI matrix builds all four targets and uploads artifacts
• Husky pre-commit hook enforces dotnet-format

Types of Changes

• Core
• Bugfix
• New feature
• Enhancement/optimization
• Documentation

[tzarc]

GHA workflows are currently set up so they produce binaries on my own fork, will pivot those to main QMK GitHub org closer to merge time.

[NickBrisebois]

Thank you for this! I was really surprised there wasn't already official Linux support for Toolbox when I started setting up QMK on my new keyboard today

edit: Successfully flashed my QMMK Pro with it using a firmware compiled on config.qmk.fm 😄 (Linux kernel 7.0.10-1-cachyos w/ KDE 6.6.5 on Wayland)