use custom service for hyprshade instead of installing the provided one

home-manager/hyprland/hyprshade.nix

@@ -2,16 +2,35 @@
 
 let cfg = osConfig.custom.graphical.hyprland;
 in {
-  config = lib.mkIf cfg.enable {
-    home.activation.hyprshade = {
-      after = [ "writeBoundary" ];
-      before = [ ];
-      data = ''
-        ${pkgs.hyprshade}/bin/hyprshade install
-        ${pkgs.systemd}/bin/systemctl --user enable --now hyprshade.timer
-      '';
+  config = lib.mkIf cfg.enable
+    {
+      home.file.".config/hypr/hyprshade.toml".source = ../../.config/hypr/hyprshade.toml;
+      wayland.windowManager.hyprland.settings.exec-once = [ "${pkgs.hyprshade}/bin/hyprshade auto" ];
+      systemd.user = {
+
+        services.hyprshade = {
+          Install.WantedBy = [ "graphical-session.target" ];
+
+          Unit = {
+            ConditionEnvironment = "HYPRLAND_INSTANCE_SIGNATURE";
+            Description = "Apply screen filter";
+            After = [ "graphical-session-pre.target" ];
+            PartOf = [ "graphical-session.target" ];
+          };
+          Service = {
+            Type = "oneshot";
+            ExecStart = "${pkgs.hyprshade}/bin/hyprshade auto";
+          };
+        };
+
+        timers.hyprshade = {
+
+          Install.WantedBy = [ "timers.target" ];
+
+          Unit = { Description = "Apply screen filter on schedule"; };
+
+          Timer.OnCalendar = [ "*-*-* 06:00:00" "*-*-* 19:00:00" ];
+        };
+      };
     };
-    home.file.".config/hypr/hyprshade.toml".source = ../../.config/hypr/hyprshade.toml;
-    wayland.windowManager.hyprland.settings.exec-once = [ "${pkgs.hyprshade}/bin/hyprshade auto" ];
-  };
 }