fix(web): add CSS stub loader for Payload CMS route collection in Docker

Node ESM can't handle .css imports during Next.js route collection.
This loader intercepts .css resolutions and returns empty modules,
fixing the build for all Payload deps (richtext-lexical, react-image-crop, etc.)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/web/css-stub-loader.mjs

@@ -0,0 +1,31 @@
+/**
+ * Node.js ESM custom loader — stubs .css imports as empty modules.
+ *
+ * Next.js 16 does route collection in raw Node ESM (not webpack/turbopack).
+ * Payload CMS dependencies import .css files which Node can't handle.
+ * This loader intercepts .css resolutions and returns an empty module.
+ *
+ * Usage: NODE_OPTIONS="--import ./apps/web/css-stub-loader.mjs"
+ */
+
+import { register } from "node:module";
+
+register(
+  "data:text/javascript," +
+    encodeURIComponent(`
+export function resolve(specifier, context, nextResolve) {
+  if (specifier.endsWith('.css')) {
+    return { url: 'data:text/javascript,export default {};', shortCircuit: true };
+  }
+  return nextResolve(specifier, context);
+}
+
+export function load(url, context, nextLoad) {
+  if (url.endsWith('.css')) {
+    return { format: 'module', source: 'export default {};', shortCircuit: true };
+  }
+  return nextLoad(url, context);
+}
+`),
+  import.meta.url,
+);