refactor(fuchsia): reorganize audio and bluetooth configuration

Separated PipeWire audio configuration from bluetooth hardware settings for
better logical organization. Moved bluetooth config to hardware-configuration.nix
alongside kernel module workarounds (disable_ertm, iwlwifi power_save).

Also added documentation for permittedInsecurePackages in global config and
updated flake dependencies.

nixos/fuchsia/services/pipewire/default.nix

@@ -1,19 +0,0 @@
-{ pkgs, ... }: {
-  # Realtime scheduler
-  security.rtkit.enable = true;
-
-  # Sound server
-  services.pipewire = {
-    enable = true;
-
-    # Enable components
-    alsa.enable = true;
-    alsa.support32Bit = true;
-    pulse.enable = true;
-  };
-
-  # Sound mixer
-  environment.systemPackages = with pkgs; [
-    pulsemixer
-  ];
-}