feat(build): enable distributed builds and caching setup

- Added Nix distributed build configuration for multiple machines.
- Introduced caching setup with substituters and sandbox paths.
- Enabled optional build configurations with ccache support.

modules/darwin/services/build/default.nix

@@ -0,0 +1,17 @@
+{ config
+, lib
+, pkgs
+, ...
+}:
+with lib;
+with lib.metacfg;
+let
+  cfg = config.metacfg.build;
+in
+{
+  options.metacfg.build = with types; {
+    enable = mkBoolOpt false "Whether or not to enable the build config.";
+  };
+
+  config = mkIf cfg.enable { };
+}

modules/nixos/services/base/default.nix

@@ -1,8 +1,7 @@
-{
+{ config
-  config,
+, lib
-  lib,
+, pkgs
-  pkgs,
+, ...
-  ...
 }:
 with lib;
 with lib.metacfg;

modules/nixos/services/build/default.nix

@@ -0,0 +1,23 @@
+{ config
+, lib
+, pkgs
+, ...
+}:
+with lib;
+with lib.metacfg;
+let
+  cfg = config.metacfg.build;
+in
+{
+  options.metacfg.build = with types; {
+    enable = mkBoolOpt false "Whether or not to enable the build config.";
+  };
+
+  config = mkIf cfg.enable {
+    programs.ccache.enable = true;
+    nix.settings.extra-sandbox-paths = [ "/var/cache/ccache" ];
+    environment.systemPackages = [
+      pkgs.ccache
+    ];
+  };
+}

systems/aarch64-darwin/m4/default.nix

@@ -4,6 +4,45 @@ with lib.metacfg;
 {
   system.defaults.dock.autohide = false;
 
+  nix.distributedBuilds = true;
+
+  nix.buildMachines = [
+    {
+      hostName = "m1.local";
+      system = "aarch64-darwin";
+      maxJobs = 4;
+      speedFactor = 2;
+      sshUser = "harald";
+      sshKey = "/etc/ssh/nix-builder-key";
+    }
+    {
+      hostName = "rialo.local";
+      system = "aarch64-darwin";
+      maxJobs = 4;
+      speedFactor = 2;
+      sshUser = "harald";
+      sshKey = "/etc/ssh/nix-builder-key";
+    }
+    {
+      hostName = "sgx.local";
+      system = "x86_64-linux";
+      maxJobs = 4;
+      speedFactor = 1;
+      sshUser = "harald";
+      sshKey = "/etc/ssh/nix-builder-key";
+    }
+  ];
+
+  nix.settings = {
+    substituters = [
+      "https://cache.nixos.org"
+      "ssh-ng://harald@m4.local?ssh-key=/etc/ssh/nix-builder-key"
+      "ssh-ng://harald@rialo.local?ssh-key=/etc/ssh/nix-builder-key"
+    ];
+
+    builders-use-substitutes = true;
+  };
+
   homebrew = {
     enable = true;
     brews = [
@@ -27,6 +66,7 @@ with lib.metacfg;
       direnv.enable = true;
       alacritty.enable = true;
     };
+    build.enable = true;
   };
 
   environment.systemPackages = with pkgs; [

systems/aarch64-darwin/rialo/default.nix

@@ -2,6 +2,48 @@
 
 with lib.metacfg;
 {
+
+
+  nix.distributedBuilds = true;
+
+  nix.buildMachines = [
+    {
+      hostName = "m1.local";
+      system = "aarch64-darwin";
+      maxJobs = 4;
+      speedFactor = 2;
+      sshUser = "harald";
+      sshKey = "/etc/ssh/nix-builder-key";
+    }
+    {
+      hostName = "rialo.local";
+      system = "aarch64-darwin";
+      maxJobs = 4;
+      speedFactor = 2;
+      sshUser = "harald";
+      sshKey = "/etc/ssh/nix-builder-key";
+    }
+    {
+      hostName = "sgx.local";
+      system = "x86_64-linux";
+      maxJobs = 4;
+      speedFactor = 1;
+      sshUser = "harald";
+      sshKey = "/etc/ssh/nix-builder-key";
+    }
+  ];
+
+  nix.settings = {
+    substituters = [
+      "https://cache.nixos.org"
+      "ssh-ng://harald@m4.local?ssh-key=/etc/ssh/nix-builder-key"
+      "ssh-ng://harald@rialo.local?ssh-key=/etc/ssh/nix-builder-key"
+    ];
+
+    builders-use-substitutes = true;
+  };
+
+
   homebrew = {
     enable = true;
     brews = [
@@ -25,6 +67,7 @@ with lib.metacfg;
       direnv.enable = true;
       alacritty.enable = true;
     };
+    build.enable = true;
   };
 
   environment.systemPackages = with pkgs; [