Add role-based access control with admin/editor roles

Create adminOnly and adminOrEditor access functions. Add role field
to Users collection (admin/editor, default: editor). Update access control
across all collections and globals to enforce role-based permissions.

apps/backend/src/collections/Portfolio/index.ts

@@ -1,16 +1,16 @@
 import type { CollectionConfig } from 'payload'
 
-import { authenticated } from '../../access/authenticated'
 import { anyone } from '../../access/anyone'
+import { adminOrEditor } from '../../access/adminOrEditor'
 import { slugField } from '@/fields/slug'
 
 export const Portfolio: CollectionConfig = {
   slug: 'portfolio',
   access: {
-    create: authenticated,
+    create: adminOrEditor,
     read: anyone,
-    update: authenticated,
-    delete: authenticated,
+    update: adminOrEditor,
+    delete: adminOrEditor,
   },
   admin: {
     useAsTitle: 'title',