Enable notify client and replace swww with awww

- Add `notify.enable = true` to Garand-Desktop, Garand-Laptop, and
  default hosts
- Replace `swww` with `awww` in `essentials.nix`
- Expose `notify-client` in the core packages mapping

modules/core/packages/essentials.nix

@@ -58,7 +58,7 @@
     app2unit
     gpu-screen-recorder
     # hyprland
-    swww
+    awww
     grim
     slurp
     wl-clipboard

modules/core/packages/packages.nix

@@ -51,6 +51,7 @@
     teams = teams-for-linux;
     ferdium = ferdium;
     logisim-evolution = logisim-evolution;
+    notify = notify-client;
   };
 in {
   imports = builtins.attrValues (builtins.mapAttrs mkPackage packages);