fix(admin): unblock product create page

Two bugs compounded to render /admin/collections/products/create blank:

1. Dockerfile's STRIPE_SECRET_KEY build-time placeholder was too short
   (11 chars) to pass the regex that gates Stripe plugin sync. Build
   produced an importMap missing plugin-stripe components like LinkToDoc,
   warning at runtime and failing to render.

2. With autosave enabled, Payload creates a blank draft on page load.
   Plugin-stripe's beforeValidate hook fired against empty data, calling
   Stripe products.create with no name, throwing a 500 that aborted the
   page render.

Fix: use a 20+ char placeholder in the Dockerfile so the build-time
importMap mirrors runtime, and add a beforeValidate hook that sets
skipSync=true whenever productDisplayName is empty so Stripe sync
waits until the product has content.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

nextjs/Dockerfile

@@ -24,7 +24,7 @@ COPY . .
 ENV NEXT_TELEMETRY_DISABLED=1
 ENV PAYLOAD_SECRET=build-time-placeholder
 ENV DATABASE_URL=postgres://placeholder:placeholder@localhost:5432/placeholder
-ENV STRIPE_SECRET_KEY=sk_test_placeholder
+ENV STRIPE_SECRET_KEY=sk_test_abcdefghijklmnopqrstuvwxyz1234567890
 ENV NEXT_PUBLIC_SERVER_URL=https://rebours.studio
 
 RUN pnpm build

nextjs/src/app/(payload)/admin/importMap.js

@@ -1,8 +1,10 @@
+import { LinkToDoc as LinkToDoc_2e9be70cd13299dd4a11a5bd739a5a3c } from '@payloadcms/plugin-stripe/client'
 import { default as default_7060fcf8de405c49f267d6b95f29dcb7 } from '@/components/admin/ProductPreviewEditor'
 import { CollectionCards as CollectionCards_f9c02e79a4aed9a3924487c0cd4cafb1 } from '@payloadcms/next/rsc'
 
 /** @type import('payload').ImportMap */
 export const importMap = {
+  "@payloadcms/plugin-stripe/client#LinkToDoc": LinkToDoc_2e9be70cd13299dd4a11a5bd739a5a3c,
   "@/components/admin/ProductPreviewEditor#default": default_7060fcf8de405c49f267d6b95f29dcb7,
   "@payloadcms/next/rsc#CollectionCards": CollectionCards_f9c02e79a4aed9a3924487c0cd4cafb1
 }

nextjs/src/collections/Products.ts

@@ -28,6 +28,16 @@ export const Products: CollectionConfig = {
   access: {
     read: () => true,
   },
+  hooks: {
+    beforeValidate: [
+      ({ data }) => {
+        if (!data?.productDisplayName) {
+          return { ...data, skipSync: true }
+        }
+        return data
+      },
+    ],
+  },
   versions: {
     drafts: {
       autosave: { interval: 800 },