fix audio issue; update profile config

profiles/gaea/hardware.nix

@@ -4,7 +4,19 @@
 { config, lib, pkgs, modulesPath, username, ... }:
 
 {
- 
+
+  # set hdmi audio default device
+  hardware.pulseaudio = {
+    enable = true;
+    support32Bit = true;
+    extraConfig = "set-card-profile 1 output:alsa_output.pci-0000_00_1f.3.hdmi-stereo";
+  };
+
+  environment.systemPackages = with pkgs;[
+    # audio control software
+    pamixer
+  ];
+
   fileSystems."/home/${username}/tmp" =
     {
       device = "none";