refactor(fws-keys): make keyboard shortcuts tool universal for hyprland and i3

Rename fws-hypr-keys to fws-keys and extend it to support both Hyprland and i3 desktop environments. The tool now detects the session type and uses appropriate methods:

- Hyprland: queries hyprctl binds for real loaded bindings (wofi dmenu)
- i3: parses ~/.config/i3/config with variable resolution (rofi dmenu)

Update all references in configs and templates. Add VM detection warning in fws-vr-setup to prevent VR attempts in virtual machines where GPU/USB access is unavailable.

Add ttf-liberation font dependency for Steam UI stability on minimal installations and improve error guidance for Steam crashes.

configs/releng/airootfs/usr/local/share/fws/picom.conf

@@ -0,0 +1,19 @@
+# FWS — picom minimal (session i3) : coins arrondis comme sous Hyprland.
+# xrender : fiable partout, y compris en VM (rendu logiciel) ; pas de flou ni
+# d'ombres (parité avec la config Hyprland FWS, et léger pour la VR).
+backend = "xrender";
+vsync = true;
+
+corner-radius = 8;
+rounded-corners-exclude = [
+  "window_type = 'dock'",       # polybar gère son propre arrondi
+  "class_g = 'i3-frame'"
+];
+
+shadow = false;
+fading = true;
+fade-in-step = 0.08;
+fade-out-step = 0.08;
+
+# VR / jeux plein écran : ne pas composer par-dessus (latence).
+unredir-if-possible = true;