add(flatpak): some auto-installation on .flatpak extension.

will remain unused for now...

home/hakase.nix

@@ -6,6 +6,7 @@
 }: {
   imports = [
     ../modules/home/terminal.nix
+    # ../modules/home/flatpak.nix
     ../modules/home/apps.nix
     ../modules/home/apps-optional.nix
     ../modules/home/hyprland.nix

modules/home/flatpak.nix

@@ -0,0 +1,25 @@
+{pkgs, ...}: let
+  flatpak-install = pkgs.writeShellScriptBin "flatpak-install" ''
+    flatpak install --user --bundle "$1"
+    echo
+    read -p "Press Enter to close..."
+  '';
+in {
+  home.packages = [flatpak-install];
+
+  xdg.mimeApps = {
+    enable = true;
+    defaultApplications = {
+      "application/vnd.flatpak" = "flatpak-bundle-installer.desktop";
+    };
+  };
+
+  xdg.desktopEntries.flatpak-bundle-installer = {
+    name = "Flatpak Bundle Installer";
+    exec = "flatpak-install %f";
+    terminal = true;
+    noDisplay = true;
+    type = "Application";
+    mimeType = ["application/vnd.flatpak"];
+  };
+}