feat(nixos): migrate AdGuard to Pikachu

configs/nixos/guests/adguard.nix

@@ -0,0 +1,29 @@
+{
+  config,
+  lib,
+  ...
+}:
+let
+  cfg = config.guests.adguard;
+in
+{
+  options.guests.adguard.adminPasswordHash = lib.mkOption {
+    type = lib.types.str;
+    description = "Bcrypt verifier for the AdGuard Home administrator password.";
+  };
+
+  config = lib.mkIf cfg.enable {
+    guests.adguard = {
+      interior.modules.services.adguardhome = {
+        enable = true;
+        inherit (cfg) adminPasswordHash;
+      };
+
+      limits = {
+        memory = lib.mkDefault "256M";
+        cpu = lib.mkDefault "100%";
+        tasksMax = lib.mkDefault 128;
+      };
+    };
+  };
+}