Enhance user verification and UI components

- Updated `auth-actions.ts` to improve user verification notification formatting and date handling.
- Modified `layout.tsx` to support dark mode styling for better user experience.
- Refactored `signup/page.tsx` to enhance layout and responsiveness.
- Introduced a new API route in `route.ts` for sending user verification notifications.
- Improved user feedback in `user-payments-table.tsx` by updating the no payment message.
- Made minor adjustments in `application-layout.tsx` for consistent padding.
- Enhanced `signup-form.tsx` to display error messages for invalid user validation.

These changes improve the user verification process, enhance UI consistency, and provide better feedback to users.

app/(auth)/signup/page.tsx

@@ -29,15 +29,9 @@ export default async function SignupPage({
 	});
 
 	return (
-		<div className="dark:bg-black w-full flex items-center justify-center font-sans">
-			<div className="flex flex-col items-center justify-center w-full h-full py-4">
-				<Image
-					priority
-					alt="Sar Link Logo"
-					src="/logo.png"
-					width={100}
-					height={100}
-				/>
+		<div className="dark:bg-black w-full h-screen flex items-center justify-center font-sans">
+			<div className="flex flex-col items-center justify-center w-full h-full ">
+				<Image alt="Sar Link Logo" src="/logo.png" width={100} height={100} />
 				<div className="mt-4 flex flex-col items-center justify-center">
 					<h4 className="font-bold text-xl text-gray-600">SAR Link Portal</h4>
 					<p className="text-gray-500">