Create auth confirmation route

Added a new route for authentication confirmation that uses OTP verification. If successful, it redirects the user to the specified next path; otherwise, it navigates them to an error page. This is part of implementing more robust user authentication.

apps/web/app/auth/confirm/route.ts

@@ -0,0 +1,33 @@
+import { NextRequest, NextResponse } from 'next/server';
+
+import { type EmailOtpType } from '@supabase/supabase-js';
+
+import { getSupabaseRouteHandlerClient } from '@kit/supabase/route-handler-client';
+
+export async function GET(request: NextRequest) {
+  const { searchParams } = new URL(request.url);
+  const token_hash = searchParams.get('token_hash');
+  const type = searchParams.get('type') as EmailOtpType | null;
+  const next = searchParams.get('next') ?? '/';
+  const redirectTo = request.nextUrl.clone();
+
+  redirectTo.pathname = next;
+
+  if (token_hash && type) {
+    const supabase = getSupabaseRouteHandlerClient();
+
+    const { error } = await supabase.auth.verifyOtp({
+      type,
+      token_hash,
+    });
+
+    if (!error) {
+      return NextResponse.redirect(redirectTo);
+    }
+  }
+
+  // return the user to an error page with some instructions
+  redirectTo.pathname = '/auth/callback/error';
+
+  return NextResponse.redirect(redirectTo);
+}