feat: add global theme mode and Yazi shortcut

- Added theme.mode to config.nix for global dark/light mode control.
- Updated Matugen to apply GTK dark mode preferences based on the global theme.
- Added a Hyprland bind (SUPER+X) to launch Yazi via uwsm.

apps/matugen/default.nix

@@ -352,6 +352,15 @@
     platformTheme.name = "gtk";
   };
 
+  dconf.settings = {
+    "org/gnome/desktop/interface" = {
+      color-scheme =
+        if myConfig.theme.mode == "dark"
+        then "prefer-dark"
+        else "prefer-light";
+    };
+  };
+
   # GTK theming with adw-gtk3 and Matugen colors
   gtk = {
     enable = true;
@@ -364,7 +373,19 @@
       package = pkgs.papirus-icon-theme;
     };
     gtk3.extraCss = ''@import url("colors.css");'';
+    gtk3.extraConfig = {
+      gtk-application-prefer-dark-theme =
+        if myConfig.theme.mode == "dark"
+        then 1
+        else 0;
+    };
     gtk4.extraCss = ''@import url("colors.css");'';
+    gtk4.extraConfig = {
+      gtk-application-prefer-dark-theme =
+        if myConfig.theme.mode == "dark"
+        then 1
+        else 0;
+    };
   };
 
   programs.ghostty.settings.theme = "matugen";