feat: add musnix for realtime audio

modules/linux/audio-prod/default.nix

@@ -6,25 +6,53 @@
 }:
 let
   cfg = config.liminalOS.system.audio.prod;
+  forAllUsers = lib.genAttrs cfg.realtimeAudioUsers;
 in
 {
-  options.liminalOS.system.audio.prod.enable = lib.mkEnableOption "audio production";
+  options.liminalOS.system.audio.prod = {
+    enable = lib.mkEnableOption "audio production";
+    realtimeAudioUsers = lib.mkOption {
+      type = lib.types.listOf lib.types.str;
+      default = [ ];
+      description = ''
+        List of users to add to the audio group for realtime capabilities.
+      '';
+    };
+  };
 
-  config = lib.mkIf cfg.enable {
-    liminalOS = {
+  config = {
+    liminalOS = lib.mkIf cfg.enable {
       programs.wine.enable = true;
       system.audio.enable = true;
+      config.extraUnfreePackages = lib.mkIf config.liminalOS.config.allowUnfree [
+        "reaper"
+      ];
     };
 
-    environment.systemPackages = with pkgs; [
-      reaper
-      yabridge
-      yabridgectl
-      alsa-scarlett-gui
-    ];
+    environment.systemPackages = lib.mkIf cfg.enable (
+      (with pkgs; [
+        yabridge
+        yabridgectl
+        alsa-scarlett-gui
+      ])
+      ++ (lib.optionals config.liminalOS.config.allowUnfree [
+        pkgs.reaper
+      ])
+    );
 
-    liminalOS.config.extraUnfreePackages = lib.mkIf config.liminalOS.config.allowUnfree [
-      "reaper"
+    musnix.enable = cfg.enable;
+    # PREEMPT_RT is merged into master
+    musnix.kernel.realtime = false;
+
+    musnix.das_watchdog.enable = cfg.enable;
+    musnix.alsaSeq.enable = cfg.enable;
+    musnix.rtcqs.enable = cfg.enable;
+    users.users = forAllUsers (_: {
+      extraGroups = [ "audio" ];
+    });
+
+    boot.kernelParams = lib.mkIf cfg.enable [
+      "threadirqs"
     ];
   };
 }