feat(nix): enhance systemd-email-notify service configuration

- Added `StartLimitIntervalSec` and `StartLimitBurst` for `ntfy-failure@` unit.
- Refactored `ExecStart` into `script` for improved readability.
- Adjusted `scriptArgs` from `%I` to `%i`.

modules/nixos/services/systemd-email-notify/default.nix

@@ -33,8 +33,9 @@ let
     ERRMAIL
   '';
 
-  onFailureUnits =
+  onFailureUnits = [
-    [ "email@%n.service" ]
+    "email@%n.service"
+  ]
   ++ optionals (cfg.ntfy.tokenFile != null) [ "ntfy-failure@%n.service" ];
 in
 {
@@ -103,9 +104,14 @@ in
       systemd.services."ntfy-failure@" = {
         description = "Send ntfy notification on service failure";
         onFailure = mkForce [ ];
+        unitConfig = {
+          StartLimitIntervalSec = "5m";
+          StartLimitBurst = 1;
+        };
         serviceConfig = {
           Type = "oneshot";
-          ExecStart = pkgs.writeShellScript "ntfy-failure-notify" ''
+        };
+        script = ''
           TOKEN=$(cat ${cfg.ntfy.tokenFile})
           UNIT="$1"
           ${pkgs.curl}/bin/curl -s \
@@ -116,8 +122,7 @@ in
             -d "$(systemctl status --full "$UNIT" 2>&1 | head -40)" \
             ${cfg.ntfy.url}/${cfg.ntfy.topic}
         '';
-        };
+        scriptArgs = "%i";
-        scriptArgs = "%I";
       };
     })
   ]);