feat: implement modular foundation and core system services

- Update flake.nix with 25.11 release and core inputs
- Add dedicated modules for audio (Pipewire), bluetooth, and networking
- Update GEMINI.md with the new Modular Merging Architecture blueprint
- Configure graphical installer ISO and test VM outputs

modules/system/default.nix

@@ -1,9 +1,13 @@
-{ config, pkgs, ... }:
+{ config, lib, pkgs, ... }:
 
 {
   imports = [
     ./plymouth.nix
     ./sddm.nix
     ./hardware.nix
+    ./audio.nix
+    ./bluetooth.nix
+    ./network.nix
+    ./impermanence.nix
   ];
 }