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/scripts/strip-metadata.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+
+if [ $# -eq 0 ]; then
+    echo "Usage: strip-metadata <file_or_directory>"
+    exit 1
+fi
+
+TARGET="$1"
+
+echo "[*] Stripping metadata from: $TARGET"
+
+# Remove all embedded metadata while keeping original filenames
+if command -v exiftool &> /dev/null; then
+    exiftool -all= -overwrite_original -r "$TARGET"
+    echo "[+] Exif metadata removed."
+else
+    echo "[!] Warning: exiftool is not installed."
+fi
+
+# Reset timestamps (atime and mtime) to Epoch (1970-01-01 00:00:00)
+echo "[*] Resetting timestamps..."
+find "$TARGET" -exec touch -t 197001010000.00 {} +
+
+echo "[+] Operation completed successfully."