Add Linux support and UI scaling

[xlab]

Hello! These 2 commits add Linux support, I have verified on my Arch setup.

List of changes:

1. WEBKIT_DISABLE_COMPOSITING_MODE is on for Linux, because Tauri is glitched on Nvidia cards, it is a long going problem with Tauri. It doesn't affect visuals or performance of this app.

2. Added UI scaling setting, this is important because on Linux scaling always has to be adjusted manually. This is on par with VSCode - shortcuts (Ctrl++ / Ctrl+-/Ctrl+0) are there. Scaling also works on macOS perfectly (use Cmd key). The scaling setting persists between restarts.

3. Added AppImage building support and CI. CI builds for both x86_64 and arm64.

AppImage builds locally via npm run build:appimage, but in CI you have to figure out how to set priv key for signing.

UI scaling setting:

CI message on release:

UI scaling at work:
https://x.com/xlab_os/status/2011245882918981648

[Dimillian]

This is so cool! Thanks! Will look soon.
FYI: Fow now I do release locally using the RELEASING.MD so would be cool if you can update, or ask Codex to update it to include a linux image in the release.
I'll soon look at how to have the release in as a manual workflow like you did, but for now I find it easier to let an agent drive it than to debug a CI script

[xlab]

@Dimillian yeah I get that :)
Will check how to modify that skill.

[xlab]

2 minutes ago

Damn I am cherry-picking on the fly xD
must... get.. upfront...

[xlab]

Ok @Dimillian I think this done. I've rebased the branch to have clean diff, removed CI config

Added RELEASING.linux.md with similar structure for instructions. Obviously it has to be in correct environment and arch, i.e. no possible to build for Linux from macOS without a Docker, QEMU or something.

[Dimillian]

@xlab yeap but at least people on Linux will be able to build it while I get the release sorted out. I guess I do it a way to maka it a workflow from GH, will look into it soon I hope

[xlab]

@Dimillian
Thanks for the merge!!

I'm building AppImages from my fork for now:
https://github.com/xlab/CodexMonitor/releases

There is the CI job definition I use:
https://github.com/xlab/CodexMonitor/blob/bd561aaeeebecc55d91ac86883fed9fecba2aeb6/.github/workflows/build-appimage.yaml

Good luck!