Support Arch Linux ARM64 and Omarchy for the Codex desktop app

Request

Please consider official support for the Codex desktop app on Arch Linux ARM64 and Omarchy.

Why

Omarchy is an Arch-based Hyprland desktop used for development. The official Linux preview supports Ubuntu, Debian, and Fedora packages, but not Arch-based systems, even though the official ARM64 payload runs successfully on Arch Linux ARM64.

Working implementation

I built a small Omarchy-facing Arch package from the official OpenAI ARM64 .deb:

• Downloads directly from OpenAI's package repository.
• Verifies the pinned upstream SHA-256 checksum.
• Repackages the .deb as an Arch package.
• Adds a codex launcher command.
• Adds a Codex application-menu entry and Codex-branded icon.
• Does not modify the bundled application code or install a third-party updater.

Implementation and smoke test:
https://github.com/anujraja/codex/tree/omarchy/packaging/omarchy

The package smoke test passed on Omarchy/Arch Linux ARM64. It verifies the OpenAI source checksum, builds the package, checks Arch package metadata, confirms the required ARM64 payload and launcher files, and validates the desktop entry.

I understand the repository's contribution policy and am sharing this as a feature request and implementation reference rather than requesting that this branch be merged directly.

Start with the referenced packaging/omarchy implementation and its smoke-test steps, then inspect how the repository currently packages the Linux desktop app for Ubuntu, Debian, and Fedora. Done means an official Arch Linux ARM64 and Omarchy package with the described checksum verification, launcher, application-menu entry, icon, and passing smoke test.