Switch desktop environment from Hyprland to Pantheon

Configures Pantheon (LightDM + gala) for daily use on this ASUS TUF
Gaming A15 (FA507NU), and drops everything that only existed to serve
the previous Hyprland/Quickshell setup:

- desktop.nix: services.desktopManager.pantheon instead of
  programs.hyprland + greetd; comfy laptop touchpad defaults.
- drivers.nix: NVIDIA PRIME render offload between the AMD Radeon 680M
  (drives the panel) and the RTX 4050 Max-Q (offload-only), using this
  machine's real PCI bus IDs; asusd/supergfxd for ASUS-specific laptop
  control.
- apps.nix / scripts.nix: removed Hyprland/Quickshell-only packages and
  scripts (kitty, rofi, quickshell, mako, hyprlock, hyprpaper/mpvpaper,
  the Quickshell theme-picker scripts, cursor/wallpaper/display
  helpers) — Pantheon ships its own Files/Terminal/Screenshot/
  notifications/theming natively. Kept the DE-agnostic scripts (vault
  toggle, metadata stripping, brightness control, Wi-Fi hotspot,
  telemetry, weather).
- theme.nix and default-apps.nix deleted entirely — Pantheon owns
  GTK/icon theming itself, no more live dconf/CSS generation pipeline
  needed.
- Deleted hyprland/ and dotfiles/ (kitty, mako, quickshell, rofi).

Verified with `nixos-rebuild build`.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RpiovBQL6k5MTDMN3Ln9nL

modules/desktop.nix

@@ -0,0 +1,38 @@
+{ config, pkgs, ... }:
+
+{
+  # --- Pantheon: elementary OS's desktop environment (gala compositor, Wayland) ---
+  # Pulls in its own session (pantheon-wayland), top panel (Wingpanel), dock,
+  # app launcher, Files, Terminal, Screenshot, Photos, notifications, and
+  # GTK/icon theming — no separate compositor config or dotfile symlinking
+  # needed, unlike the previous Hyprland setup.
+  services.xserver.enable = true;
+  services.xserver.displayManager.lightdm.enable = true;
+  services.desktopManager.pantheon.enable = true;
+
+  # Keyboard layout for LightDM/XWayland; Pantheon's own session picks this
+  # up too.
+  services.xserver.xkb = {
+    layout = "pl";
+    variant = "";
+  };
+
+  security.polkit.enable = true;
+
+  # Native Wayland backend for Electron/Chromium-based apps
+  environment.sessionVariables.NIXOS_OZONE_WL = "1";
+
+  # Comfortable trackpad defaults for a laptop — tap-to-click and natural
+  # scrolling aren't on by default, and gala reads touchpad settings from
+  # GSettings at runtime (not services.libinput, which is X11-only), so
+  # they're set here as a dconf default instead.
+  programs.dconf.profiles.user.databases = [
+    {
+      settings."org/gnome/desktop/peripherals/touchpad" = {
+        tap-to-click = true;
+        natural-scroll = true;
+        two-finger-scrolling-enabled = true;
+      };
+    }
+  ];
+}