✨ [pi4] Added initial Simple mailserver config

hosts/pi4/mailserver.nix

@@ -0,0 +1,55 @@
+{
+  lib,
+  config,
+  inputs,
+  common,
+  systemConfig,
+  ...
+}:
+let
+  cfg = config.mailserver;
+  passwordHashKey = "mailserver/password-hash";
+in
+{
+  imports = [
+    inputs.simple-nixos-mailserver.nixosModule
+  ];
+
+  mailserver = {
+    enable = true;
+    # stateVersion = 1; TODO uncomment on 25.11
+    fqdn = "mail.${common.domain}";
+    domains = [
+      common.domain
+    ];
+
+    # A list of all login accounts. To create the password hashes, use
+    # nix-shell -p mkpasswd --run 'mkpasswd -sm bcrypt'
+    loginAccounts = {
+      "${systemConfig.username}@${common.domain}" = {
+        hashedPasswordFile = config.sops.secrets.${passwordHashKey}.path;
+      };
+    };
+
+    # Use Let's Encrypt certificates. Note that this needs to set up a stripped
+    # down nginx and opens port 80.
+    # certificateScheme = "acme-nginx";
+  };
+  # security.acme.acceptTerms = true;
+  # security.acme.defaults.email = "security@example.com";
+
+  services.nginx.virtualHosts.${cfg.fqdn}.listen = lib.mkForce [
+    {
+      addr = "127.0.0.1";
+      port = 8003;
+      ssl = false;
+    }
+    {
+      addr = "192.168.10.188";
+      port = 8003;
+      ssl = false;
+    }
+  ];
+
+  sops.secrets.${passwordHashKey}.neededForUsers = true;
+}