Add Copilot instructions, update flake.lock, and enhance Nix configurations

- Introduced Copilot instructions for better project understanding.
- Updated flake.lock with new dependency revisions and hashes.
- Modified zen.nix to include tracking protection and native messaging hosts.
- Added godot.nix for Godot language support in VSCode.
- Enhanced kde.nix with additional system packages and session variables.
- Created thunderbolt.nix to enable Thunderbolt services.
- Updated Bellerophon default.nix to include thunderbolt.nix.
- Adjusted hardware-configuration.nix to include new kernel modules and parameters.

hosts/common/optional/kde.nix

@@ -1,5 +1,7 @@
-{
+{pkgs, ...}: {
   services.desktopManager.plasma6.enable = true;
   environment.sessionVariables.GTK_USE_PORTAL = "1";
   environment.sessionVariables.NIXOS_OZONE_WL = "1";
+  environment.sessionVariables.KWIN_DRM_PREFER_COLOR_DEPTH = "24";
+  environment.systemPackages = with pkgs.kdePackages; [plasma-thunderbolt sddm-kcm];
 }