feat: update theme management across the application; change default theme to 'light', disable system theme option, and add ThemeCard component in settings for enhanced user customization

components/ui/sonner.tsx

@@ -4,11 +4,11 @@ import { useTheme } from "next-themes";
 import { Toaster as Sonner, ToasterProps } from "sonner";
 
 const Toaster = ({ ...props }: ToasterProps) => {
-  const { theme = "system" } = useTheme();
+  const { theme = "light" } = useTheme();
 
   return (
     <Sonner
-      theme={theme as ToasterProps["theme"]}
+      theme={theme === "system" ? "dark" : (theme as ToasterProps["theme"])}
       className="toaster group"
       style={
         {