Fix signup button rendering

Replaced DropdownMenuItem for signup with a full-width button inside a padded div to ensure a visible red border frame. Hover/focus opacity preserved via hover:bg-red-600/30.

X-Lovable-Edit-ID: edt-67e0f7fb-c7fa-4955-a367-78b4f401e68c

src/components/AccountMenu.tsx

@@ -58,12 +58,14 @@ const AccountMenu = () => {
             </>
           ) : (
             <>
-              <DropdownMenuItem
+              <div className="px-1 py-1">
+                <button
                   onClick={() => handleOpenAuth("signup")}
-                className="cursor-pointer font-bold border-2 border-red-600 rounded-md mx-1 my-1 hover:bg-red-600/30 focus:bg-red-600/30"
+                  className="w-full px-3 py-2 text-left font-bold border-2 border-red-600 rounded-md hover:bg-red-600/30 transition-colors"
                 >
                   Skapa konto
-              </DropdownMenuItem>
+                </button>
+              </div>
               <DropdownMenuItem
                 onClick={() => handleOpenAuth("login")}
                 className="cursor-pointer flex items-center gap-2"