Add an isolated Linux AppImage port under linux/

[bguetter]

Summary

Adds a Linux port of Codenotch as a portable x86_64 AppImage, kept entirely under linux/ so the Swift macOS app and the Windows Tauri tree stay untouched.

This is a contribution for maintainers to consider, not a claim that Linux is a first-class platform yet. It was built so people already running Fedora/Bazzite or Ubuntu can try the same notch, tray meters, Settings, and hover usage card as Windows.

The AppImage binary is not committed. CI builds it (.github/workflows/linux-package.yml) and uploads linux/Codenotch.AppImage as an artifact; on v* releases it can be attached next to the dmg and the Windows installer.

Where it runs

This is not a “runs on every Linux” binary. It is an x86_64 glibc AppImage, linked on Ubuntu 22.04 (glibc 2.35) so one file can run on newer desktops.

Distro	Status
Fedora / Bazzite / Nobara	Tested on Bazzite (KDE). Install host webkit2gtk4.1.
Ubuntu 22.04, 24.04 and derivatives (Mint, Pop!_OS)	Same glibc family the binary is linked against.
Debian 12+	Needs libwebkit2gtk-4.1-0.
Other glibc x86_64 desktops (Arch, openSUSE Tumbleweed, …)	Untested; should work if they ship webkit2gtk-4.1 and FUSE.

Will not run: ARM/aarch64, musl (Alpine), Ubuntu 20.04 / Debian 11 and older glibc, machines without webkit2gtk-4.1.

Host packages at runtime:

• webkit2gtk-4.1 + GTK 3 (Fedora: webkit2gtk4.1; Ubuntu/Debian: libwebkit2gtk-4.1-0)
• FUSE to mount the AppImage
• An AppIndicator tray (KDE usually has one; GNOME needs an extension)

Run it on the host, not inside Distrobox. Config: ~/.config/codenotch.

Desktop caveats:

• KDE / X11 (typical Bazzite): always-on-top pill and hover card work.
• GNOME Wayland: the compositor often ignores always-on-top. Tray + Settings still show the meters; the overlay notch is best-effort.

Full table: linux/README.md.

Why a thin AppImage (host WebKit)

A full linuxdeploy bundle that ships Ubuntu’s WebKitGTK crashes on Fedora/Bazzite (EGL_BAD_PARAMETER). Settings and the notch stay blank.

So the shipped file is a thin AppImage (~5 MB): cargo binary + codenotch-hook sidecar, and the host’s webkit2gtk-4.1 at runtime. pack-appimage-host-webkit.sh strips the bundled Ubuntu WebKit after Tauri packs.

Build on Ubuntu 22.04 (or a Distrobox of that image). A native Fedora host build links a newer glibc and may not run on Ubuntu 22.04.

Changes

• New linux/ tree: Rust + Tauri 2 / WebKitGTK, same providers as Windows (Claude, Codex, Cursor, Grok, Antigravity).
• Thin AppImage pack (build-appimage.sh + pack-appimage-host-webkit.sh).
• CI: .github/workflows/linux.yml (build / test / clippy on Ubuntu 22.04) and .github/workflows/linux-package.yml (AppImage artifact; attach on v* releases).
• Root README.md Linux section and CONTRIBUTING.md Linux notes. i18n stays in linux/codenotch/src/i18n.rs — not merged with Windows or Mac.
• Install hooks copies codenotch-hook to ~/.local/share/codenotch/ so Claude Code does not point into a vanished AppImage mount.
• Linux hover card is a separate opaque Tauri window (hover.html). Painting usage inside the transparent overlay stacked previous cards and did not close reliably under WebKitGTK’s software compositor.
• Settings <select> styled for WebKitGTK (native GTK selects were white-on-white).
• windows/ is left as-is. No .AppImage or linux/target/ in git.

Test Plan

• node scripts/check-ui-scripts.mjs in linux/
• AppImage built on Ubuntu 22.04 Distrobox (codenotch-build), glibc 2.35
• Ran on Bazzite (Fedora Kinoite, KDE, x86_64): tray meters, Settings, right-edge notch
• Hover: open usage card, switch provider, close when the pointer leaves
• Settings dropdowns readable (dark background, light text)
• ./Codenotch.AppImage doctor
• CI Linux + Linux Package on this PR (Ubuntu 22.04)
• Maintainer smoke test on Ubuntu 22.04/24.04 if possible
• make test-ci (macOS suite; this PR does not change Swift sources)

Screenshots / Screen Recordings

Tested on Bazzite / KDE with the thin AppImage from ~/Downloads/Codenotch.AppImage. Happy to attach a recording if useful.

Made with Cursor