feat: add self-hosted cache server

system/modules/nixsettings.nix

@@ -3,7 +3,16 @@
   documentation.nixos.enable = false;
   nix = {
     settings = {
+      substituters = [
+        "https://cache.net.dn/dn-main"
+      ];
+      trusted-public-keys = [
+        "dn-main:ZjQmZEOWpe0TjZgHGwkgtPdOUXpN82RL9wy30EW1V7k="
+      ];
       warn-dirty = false;
+      trusted-users = [
+        "@wheel"
+      ];
       experimental-features = [
         "nix-command"
         "flakes"

system/modules/printer.nix

@@ -0,0 +1,23 @@
+{ pkgs, ... }:
+{
+  services.printing = {
+    enable = true;
+    drivers = with pkgs; [
+      gutenprint
+      gutenprintBin
+      brlaser
+      brgenml1lpr
+      brgenml1cupswrapper
+      splix
+      hplip
+      epson-escpr2
+      epson-escpr
+    ];
+  };
+
+  services.avahi = {
+    enable = true;
+    nssmdns4 = true;
+    openFirewall = true;
+  };
+}

system/modules/stalwart.nix

@@ -103,7 +103,7 @@ in
       acme."letsencrypt" = mkIf (acmeConf != null) acmeConf;
 
       session.auth = {
-        mechanisms = "[PLAIN LOGIN OAUTHBEARER]";
+        mechanisms = "[plain login oauthbearer]";
         directory = mkCondition "listener != 'smtp'" "'ldap'" false;
         require = mkCondition "listener != 'smtp'" true false;
       };
@@ -117,12 +117,6 @@ in
         "in-memory" = {
           type = "memory";
           principals = [
-            {
-              name = "danny";
-              class = "individual";
-              secret = "%{file:${adminPassFile}}%";
-              email = [ "danny@${domain}" ];
-            }
             {
               name = "postmaster";
               class = "individual";