fix(yazi): set as default handler for directories

This fixes the issue where "Show in folder" (e.g., in Firefox) would incorrectly
open other applications like Zathura. By explicitly associating 'inode/directory'
with 'yazi.desktop', folders will now open in Yazi as expected.

apps/yazi/default.nix

@@ -107,6 +107,14 @@ in {
     default=hyprland;gtk
     org.freedesktop.impl.portal.FileChooser=termfilechooser
   '';
+  
+  xdg.mimeApps = {
+    enable = true;
+    defaultApplications = {
+      "inode/directory" = "yazi.desktop";
+    };
+  };
+
   wayland.windowManager.hyprland.settings.windowrulev2 = [
     # File picker yazi - floating, centered, smaller size
     "float, class:^(org\\.hakase\\.popup\\.yazi)$"