Add support for Plasma Login Manager (PLM)

[XYenon]

Description

KDE Plasma 6.6 (released February 17, 2026) introduced Plasma Login Manager (PLM) as the successor to SDDM. It is a fork of SDDM with a new greeter frontend, wallpaper plugin integration, and a System Settings KCM module.

Major distributions are already adopting it as the default login manager:

• CachyOS — shipped in the January 2026 ISO
• Fedora 44 — approved by FESCo as the default for all KDE variants
• Arch Linux — available as plasma-login-manager package

Unlike SDDM, PLM does not support custom QML themes. Instead, its appearance is controlled through the System Settings KCM (wallpaper, color scheme, etc.), which means it relies on the Plasma color scheme and wallpaper settings.

Request

• Ensure the Catppuccin color schemes render correctly on the PLM greeter screen
• Include a matching wallpaper configuration for the login screen (all four flavours: Latte, Frappé, Macchiato, Mocha)
• Update the install script (install.sh) to optionally configure PLM settings (e.g., via /etc/plasmalogin.conf.d/)
• Document the setup for users who have migrated from SDDM to PLM

Additional context

• PLM requires systemd and will not work on systemd-free distros or BSD
• PLM is configured via /etc/plasmalogin.conf or /etc/plasmalogin.conf.d/ drop-in files
• The old SDDM theme approach is not applicable; PLM uses Plasma's own theming infrastructure
• ArchWiki: Plasma Login Manager

[ionesculiviucristian]

Good luck with that, last commit was 2 yrs ago :))