feat(yazi): enable yazi as system-wide file chooser

Configure xdg-desktop-portal-termfilechooser to use yazi (via ghostty) for file selection dialogs in portal-aware apps like Firefox. Includes a wrapper script and Hyprland window rules.

apps/yazi/default.nix

@@ -1,4 +1,15 @@
-{pkgs, ...}: {
+{
+  pkgs,
+  myConfig,
+  ...
+}: let
+  yazi-file-picker = pkgs.writeShellScriptBin "yazi-file-picker" ''
+    path="$1"
+    # multiple="$2"
+    # directory="$3"
+    ${pkgs.yazi}/bin/yazi --chooser-file="$path"
+  '';
+in {
   programs.yazi = {
     enable = true;
     enableFishIntegration = true;
@@ -11,4 +22,11 @@
       };
     };
   };
+
+  home.packages = [yazi-file-picker];
+
+  xdg.configFile."xdg-desktop-portal-termfilechooser/config".text = ''
+    [filechooser]
+    cmd=${pkgs.ghostty}/bin/ghostty --class=yazi-file-picker -e ${yazi-file-picker}/bin/yazi-file-picker
+  '';
 }