refactor(home/xdg): remove redundant default applications

Drop defaults where one desktop entry is already the sole available handler,
whether declared by the desktop or added explicitly. Keep browser defaults
because their ordering is intentional.

Assisted-by: pi (gpt-5.6-sol)

home/gabriel/features/desktop/common/wayland-wm/qutebrowser.nix

@@ -20,7 +20,6 @@ in {
     "text/xml" = ["org.qutebrowser.qutebrowser.desktop"];
     "x-scheme-handler/http" = ["org.qutebrowser.qutebrowser.desktop"];
     "x-scheme-handler/https" = ["org.qutebrowser.qutebrowser.desktop"];
-    "x-scheme-handler/qute" = ["org.qutebrowser.qutebrowser.desktop"];
   };
 
   programs.qutebrowser = {

home/gabriel/features/games/runescape/default.nix

@@ -13,11 +13,6 @@ in {
 
   home.file.".runelite/sideloaded-plugins/runelite-mcp.jar".source = "${pkgs.runelite-mcp}/share/runelite/sideloaded-plugins/runelite-mcp.jar";
 
-  xdg.mimeApps.defaultApplications = {
-    "x-scheme-handler/alt1" = "alt1lite.desktop";
-    "x-scheme-handler/rshub" = "jagex-auth-handler.desktop";
-  };
-
   home.persistence = {
     "/persist".directories = [
       ".runelite"

home/gabriel/features/productivity/khal.nix

@@ -12,14 +12,8 @@
     mimeType = ["text/calendar"];
   };
 
-  xdg.mimeApps = {
-    # pkgs.khal's desktop entry launches ikhal but declares no MIME types
-    associations.added."x-scheme-handler/calendar" = "khal.desktop";
-    defaultApplications = {
-      "text/calendar" = "khal-import.desktop";
-      "x-scheme-handler/calendar" = "khal.desktop";
-    };
-  };
+  # pkgs.khal's desktop entry launches ikhal but declares no MIME types
+  xdg.mimeApps.associations.added."x-scheme-handler/calendar" = "khal.desktop";
 
   programs.khal = {
     enable = true;