Package Screenote CLI for Arch and Omarchy

[ivankuznetsov]

Summary:

• Add a screenote-cli-git PKGBUILD and generated .SRCINFO for AUR publication.
• Install the CLI as /usr/bin/screenote through the Arch package manager.
• Document omarchy pkg aur add screenote-cli-git as the preferred Omarchy installation path.

Validation:

• Built with makepkg against the public Git source.
• Package build ran the complete Go test suite successfully.
• Verified .SRCINFO is generated from PKGBUILD.