add(anki): set .apkg files open to anki by default

mostly a personal taste. may adjust later if conflict arise

apps/anki/default.nix

@@ -1,3 +1,12 @@
 {pkgs, ...}: {
   home.packages = with pkgs; [anki-bin];
+
+  xdg.mimeApps = {
+    enable = true;
+    defaultApplications = {
+      "application/x-apkg" = "anki.desktop";
+      "application/x-anki-deck" = "anki.desktop";
+      "application/x-anki-collection" = "anki.desktop";
+    };
+  };
 }