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

hardware-configuration.nix

@@ -0,0 +1,45 @@
+# Do not modify this file!  It was generated by ‘nixos-generate-config’
+# and may be overwritten by future invocations.  Please make changes
+# to /etc/nixos/configuration.nix instead.
+{ config, lib, pkgs, modulesPath, ... }:
+
+{
+  imports =
+    [ (modulesPath + "/installer/scan/not-detected.nix")
+    ];
+
+  boot.initrd.availableKernelModules = [ "nvme" "xhci_pci" "thunderbolt" "usb_storage" "sd_mod" ];
+  boot.initrd.kernelModules = [ ];
+  boot.kernelModules = [ "kvm-amd" ];
+  boot.extraModulePackages = [ ];
+
+  fileSystems."/" =
+    { device = "/dev/disk/by-uuid/2e0afef3-e81a-45c1-a439-c17123eef182";
+      fsType = "btrfs";
+    };
+
+  fileSystems."/home" =
+    { device = "/dev/disk/by-uuid/2e0afef3-e81a-45c1-a439-c17123eef182";
+      fsType = "btrfs";
+      options = [ "subvol=home" ];
+    };
+
+  fileSystems."/nix" =
+    { device = "/dev/disk/by-uuid/2e0afef3-e81a-45c1-a439-c17123eef182";
+      fsType = "btrfs";
+      options = [ "subvol=nix" ];
+    };
+
+  fileSystems."/boot" =
+    { device = "/dev/disk/by-uuid/CA1D-BBF9";
+      fsType = "vfat";
+      options = [ "fmask=0077" "dmask=0077" ];
+    };
+
+  swapDevices =
+    [ { device = "/dev/disk/by-uuid/f52f4ee6-889e-4c86-82bf-ba8396e07483"; }
+    ];
+
+  nixpkgs.hostPlatform = lib.mkDefault "x86_64-linux";
+  hardware.cpu.amd.updateMicrocode = lib.mkDefault config.hardware.enableRedistributableFirmware;
+}