sway: enable xdg-desktop-portal-gtk

it's failing to start though

hosts/modules/gui/sway/default.nix

@@ -130,10 +130,37 @@ in
       };
 
       programs.sway = {
+        # provides xdg-desktop-portal-wlr, which exposes on dbus:
+        # - org.freedesktop.impl.portal.ScreenCast
+        # - org.freedesktop.impl.portal.Screenshot
         enable = true;
         # "wrapGAppsHook wrapper to execute sway with required environment variables for GTK applications."
         wrapperFeatures.gtk = true;
       };
+      # provide portals for:
+      # - org.freedesktop.impl.portal.Access
+      # - org.freedesktop.impl.portal.Account
+      # - org.freedesktop.impl.portal.DynamicLauncher
+      # - org.freedesktop.impl.portal.Email
+      # - org.freedesktop.impl.portal.FileChooser
+      # - org.freedesktop.impl.portal.Inhibit
+      # - org.freedesktop.impl.portal.Notification
+      # - org.freedesktop.impl.portal.Print
+      # and conditionally (i.e. unless buildPortalsInGnome = false) for:
+      # - org.freedesktop.impl.portal.AppChooser (@appchooser_iface@)
+      # - org.freedesktop.impl.portal.Background (@background_iface@)
+      # - org.freedesktop.impl.portal.Lockdown (@lockdown_iface@)
+      # - org.freedesktop.impl.portal.RemoteDesktop (@remotedesktop_iface@)
+      # - org.freedesktop.impl.portal.ScreenCast (@screencast_iface@)
+      # - org.freedesktop.impl.portal.Screenshot (@screenshot_iface@)
+      # - org.freedesktop.impl.portal.Settings (@settings_iface@)
+      # - org.freedesktop.impl.portal.Wallpaper (@wallpaper_iface@)
+      xdg.portal.extraPortals = [
+        (pkgs.xdg-desktop-portal-gtk.override {
+          buildPortalsInGnome = false;
+        })
+      ];
+
       sane.user.fs.".config/sway/config".symlink.text =
         import ./sway-config.nix { inherit pkgs; };