refactor: abstract site URL across email templates

- Add NEXT_PUBLIC_SITE_URL to .env.local
- Update email templates to accept siteUrl prop
- Update webhook handler to pass siteUrl from env var
- Update create-webhooks.graphql with placeholder URL

src/emails/OrderCancelled.tsx

@@ -16,6 +16,7 @@ interface OrderCancelledProps {
   items: OrderItem[];
   total: string;
   reason?: string;
+  siteUrl: string;
 }
 
 const translations: Record<
@@ -85,11 +86,12 @@ export function OrderCancelled({
   items,
   total,
   reason,
+  siteUrl,
 }: OrderCancelledProps) {
   const t = translations[language] || translations.en;
 
   return (
-    <BaseLayout previewText={t.preview} language={language}>
+    <BaseLayout previewText={t.preview} language={language} siteUrl={siteUrl}>
       <Text style={styles.title}>{t.title}</Text>
       <Text style={styles.greeting}>{t.greeting.replace("{name}", customerName)}</Text>
       <Text style={styles.text}>{t.orderCancelled}</Text>
@@ -124,7 +126,7 @@ export function OrderCancelled({
       </Section>
 
       <Section style={styles.buttonSection}>
-        <Button href="https://manoonoils.com" style={styles.button}>
+        <Button href={siteUrl} style={styles.button}>
           {language === "sr" ? "Pogledajte proizvode" : "Browse Products"}
         </Button>
       </Section>