fix: checkout API accessible via domain

site/checkout.md

@@ -31,7 +31,9 @@ onMounted(async () => {
   document.getElementById('status').textContent = `Creating checkout session for ${price.name}...`
 
   try {
-    const resp = await fetch('/api/checkout', {
+    // Try domain URL first, fall back to direct IP
+    const apiUrl = 'https://git.fdsa.agency/api'
+    const resp = await fetch(apiUrl, {
       method: 'POST',
       headers: { 'Content-Type': 'application/json' },
       body: JSON.stringify({