auth: show email verified banner on login page after verification

- Append ?verified=true to callbackURL in verification link
- Login page reads query param and shows green success banner
  when user lands after email verification

src/lib/server/email-verification.ts

@@ -1,11 +1,11 @@
-import { BASE_URL } from '$env/static/private';
+import { BETTER_AUTH_URL } from '$env/static/private';
 import { sendMail } from './resend';
 
 export async function sendVerificationEmail(options: {
 	email: string;
 	token: string;
 }) {
-	const verificationUrl = `${BASE_URL}/api/auth/verify-email?token=${options.token}&callbackURL=/login`;
+	const verificationUrl = `${BETTER_AUTH_URL}/api/auth/verify-email?token=${options.token}&callbackURL=/login?verified=true`;
 
 	await sendMail({
 		to: options.email,