Fix missing back-in-stock email Live Preview (404)

'back-in-stock' was added to the Payload-side email-templates type
but never wired into this repo's own EmailTemplateType union or the
Live Preview page's VALID_TYPES/fallback-heading maps — every other
type is registered in three places, this one was only in one, so
opening its Live Preview 404'd.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/email-preview/[type]/page.tsx

@@ -20,6 +20,7 @@ const VALID_TYPES: EmailTemplateType[] = [
   "order-tracking-corrected",
   "order-delivered",
   "payment-method-switched",
+  "back-in-stock",
 ];
 
 const STATUS_TYPE_FALLBACK_HEADING: Record<string, string> = {
@@ -31,6 +32,7 @@ const STATUS_TYPE_FALLBACK_HEADING: Record<string, string> = {
   "order-tracking-corrected": "Korrigierte Sendungsnummer",
   "order-delivered": "Dein Paket ist angekommen",
   "payment-method-switched": "Erledigt!",
+  "back-in-stock": "Wieder da!",
 };
 
 // Entered exclusively via EmailTemplates.ts's admin.livePreview.url (a
@@ -39,6 +41,14 @@ const STATUS_TYPE_FALLBACK_HEADING: Record<string, string> = {
 // draft:true so an unsaved edit in the admin shows up here immediately;
 // the actual sent email (orderEmail.ts) always reads the published version
 // instead.
+//
+// "back-in-stock" shares the generic order-status renderer below like
+// every other status type — an approximation, not pixel-identical (its
+// real send, lib/jobs/sendBackInStockEmails.ts on the Payload side, has no
+// order number/link at all, just a product name + "Jetzt ansehen" button),
+// same established gap as password-reset's own. Good enough to edit
+// subject/heading/bodyText/footerText live, which is what this page is
+// actually for.
 export default async function EmailPreviewPage({ params }: { params: Promise<{ type: string }> }) {
   const { type } = await params;
   if (!VALID_TYPES.includes(type as EmailTemplateType)) notFound();

app/lib/emailTemplates.ts

@@ -336,6 +336,7 @@ export const ORDER_STATUS_EMAIL_ICON: Record<string, string> = {
   "order-tracking-corrected": "📦",
   "order-delivered": "🎉",
   "payment-method-switched": "💳",
+  "back-in-stock": "🔔",
 };
 
 export function renderOrderStatusHtml(

app/lib/payload.ts

@@ -897,7 +897,8 @@ export type EmailTemplateType =
   | "order-tracking-added"
   | "order-tracking-corrected"
   | "order-delivered"
-  | "payment-method-switched";
+  | "payment-method-switched"
+  | "back-in-stock";
 
 type PayloadEmailTemplate = {
   type: EmailTemplateType;