I've been tinkering with an #Arduino extension for Nova using the PlatformIO CLI. It's sort of getting there, it installs the CLI and generates the right metadata for Panic's C++ extension to start linting. #Notes
Ideally there could be background task that generates the C/C++ metadata for the Icarus extension then some nice tasks to build and flash code onto an Arduino.
At the moment I'm not sure if PlatformIO/Arduino support the xCode based toolchains that ship with Panic's Icarus extension
I got the "sync" bit working so whenever you edit a C/C++/H or your platform.ini the extension sees that and generates a big "compiled_commands.json" which contains the information to pass to the Icarus extension and I can see that it is seeing it!
Though it seems the format of my generated file or the arguments within aren't completely compatible with the one Icarus is expecting. More research into this is needed.