feat: add COSMIC desktop, greetd DM, and transparent logo to root-overlay

- Add COSMIC desktop subgroup to online netinstall (galaxy repo)
- Add greetd as display manager option in packagechooser_dm.conf
  (required by COSMIC's cosmic-greeter)
- Replace non-transparent 900x650 logo with transparent removebg version
  at 128x92 (128x128) and 256x185 (256x256) in root-overlay icon theme paths
- Update docs to reflect COSMIC availability and greetd option

docs/desktop-environments.md

@@ -73,6 +73,15 @@ Available desktops in online mode, sourced from Artix repos.
 | **Packages** | `hyprland` |
 | **Session** | `hyprland.desktop` |
 
+## COSMIC
+
+| | |
+|---|---|
+| **Repo** | galaxy |
+| **Group** | `cosmic` |
+| **Session** | `cosmic.desktop` |
+| **Notes** | Rust-based, Wayland-native. Uses greetd + cosmic-greeter (not SDDM). Alpha quality, not for production. Works with dinit, s6, runit; OpenRC may have 100% CPU bugs |
+
 ## No Desktop
 
 Installs the base system only (TTY/login). Useful for servers or custom setups.

docs/installer.md

@@ -54,7 +54,7 @@ Dinit is preselected by default.
 
 ## Desktop selector (online)
 
-Users choose from: **Plasma**, **Xfce**, **Cinnamon**, **MATE**, **LXQt**, **i3**, **Sway**, **Hyprland**, or **No Desktop**.
+Users choose from: **Plasma**, **Xfce**, **Cinnamon**, **MATE**, **LXQt**, **i3**, **Sway**, **Hyprland**, **COSMIC**, or **No Desktop**.
 
 Implemented as a separate `packagechooser` instance with `method: legacy`. "No Desktop" installs only the base system (TTY/login — no DE, no display manager).
 
@@ -70,6 +70,7 @@ Implemented as a separate `packagechooser` instance with `method: legacy`. "No D
 | i3 | world | `i3` group | Tiling WM |
 | Sway | world | `sway` + related | Wayland-native tiling |
 | Hyprland | world | `hyprland` | Wayland compositor |
+| COSMIC | galaxy | `cosmic` group | Rust/Wayland. Uses greetd. Alpha quality |
 
 ## Not available
 

iso-profiles/antergos/live-overlay/etc/calamares-online/modules/netinstall.yaml

@@ -139,3 +139,8 @@
       packages:
         - hyprland
         - xdg-desktop-portal-hyprland
+    - name: "COSMIC"
+      description: "COSMIC Desktop (Rust/Wayland — select greetd as DM)"
+      selected: false
+      packages:
+        - cosmic

iso-profiles/antergos/live-overlay/etc/calamares/modules/packagechooser_dm.conf

@@ -29,3 +29,8 @@ items:
       name: ly
       description: "Minimal TUI display manager"
       screenshot: ""
+
+    - id: greetd
+      name: greetd
+      description: "Minimal display manager (recommended for COSMIC)"
+      screenshot: ""