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/laptop/configuration.nix

@@ -13,8 +13,8 @@ imports = [
 ../../nixos/users.nix
 ../../nixos/utils.nix
 ../../nixos/hyprland.nix
-../../nixos/usbguard.nix
-../../home/programs/helium/system.nix
+
+../../nixos/steam.nix
 
 # Machine-specific files
 ./hardware-configuration.nix
@@ -22,20 +22,6 @@ imports = [
 
 ];
 
-# Disable the author's USBGuard policy.
-
-# Generate your own after installation:
-
-#
-
-# sudo usbguard generate-policy
-
-#
-
-# Then add the generated rules and switch to a stricter policy.
-
-services.usbguard.enable = false;
-
 home-manager.users."${config.var.username}" = import ./home.nix;
 
 system.stateVersion = "24.05";