Remove unused configurations and packages from laptop setup

- Removed USBGuard configuration and its associated comments from configuration.nix.
- Cleaned up flake.nix by removing unnecessary overlays.
- Updated home.nix to remove references to Helium and Proton, and added Steam.
- Deleted secrets.default.nix and secrets.secrets.yaml files for security reasons.
- Removed Omen laptop specific configuration from omen.nix.
- Deleted vencord.nix as it is no longer needed.

hosts/home-pc/home.nix

@@ -1,8 +1,6 @@
 {config, ...}: {
   imports = [
     # Programs
-    #../../home/programs/proton
-    ../../home/programs/helium
     ../../home/programs/ghostty
     ../../home/programs/nvf
     ../../home/programs/shell
@@ -15,9 +13,9 @@
     ../../home/programs/spotatui
     ../../home/programs/yazi
 		../../home/programs/steam
+		#../../home/programs/zen
 
     ../../home/programs/group/basic-apps.nix
-    ../../home/programs/group/cybersecurity.nix
     ../../home/programs/group/dev.nix
     ../../home/programs/group/misc.nix