Add ntfy ssh login alerts. Include systemd service logs with service errors

common/ntfy/default.nix

@@ -0,0 +1,27 @@
+{ config, lib, ... }:
+
+{
+  imports = [
+    ./service-failure.nix
+    ./ssh-login.nix
+    ./zfs.nix
+  ];
+
+  options.ntfy-alerts = {
+    serverUrl = lib.mkOption {
+      type = lib.types.str;
+      default = "https://ntfy.neet.dev";
+      description = "Base URL of the ntfy server.";
+    };
+
+    curlExtraArgs = lib.mkOption {
+      type = lib.types.str;
+      default = "";
+      description = "Extra arguments to pass to curl (e.g. --proxy http://host:port).";
+    };
+  };
+
+  config = lib.mkIf config.thisMachine.hasRole."ntfy" {
+    age.secrets.ntfy-token.file = ../../secrets/ntfy-token.age;
+  };
+}