docs: improvements and additions to admin customization chapters (#13049)

www/apps/book/generated/edit-dates.mjs

@@ -19,7 +19,7 @@ export const generatedEditDates = {
   "app/learn/fundamentals/modules/container/page.mdx": "2025-05-21T15:07:12.059Z",
   "app/learn/fundamentals/workflows/execute-another-workflow/page.mdx": "2024-12-09T15:56:22.895Z",
   "app/learn/fundamentals/modules/loaders/page.mdx": "2025-06-16T13:34:16.462Z",
-  "app/learn/fundamentals/admin/widgets/page.mdx": "2024-12-09T16:43:24.260Z",
+  "app/learn/fundamentals/admin/widgets/page.mdx": "2025-07-25T12:55:14.744Z",
   "app/learn/fundamentals/data-models/page.mdx": "2025-03-18T07:55:56.252Z",
   "app/learn/fundamentals/modules/remote-link/page.mdx": "2024-09-30T08:43:53.127Z",
   "app/learn/fundamentals/api-routes/protected-routes/page.mdx": "2025-06-19T16:04:36.064Z",
@@ -29,7 +29,7 @@ export const generatedEditDates = {
   "app/learn/fundamentals/events-and-subscribers/emit-event/page.mdx": "2025-06-02T14:47:54.394Z",
   "app/learn/fundamentals/workflows/conditions/page.mdx": "2025-01-27T08:45:19.027Z",
   "app/learn/fundamentals/modules/module-link-directions/page.mdx": "2024-07-24T09:16:01+02:00",
-  "app/learn/fundamentals/admin/page.mdx": "2025-04-18T10:28:47.328Z",
+  "app/learn/fundamentals/admin/page.mdx": "2025-07-25T12:46:15.466Z",
   "app/learn/fundamentals/workflows/long-running-workflow/page.mdx": "2025-07-14T10:32:21.640Z",
   "app/learn/fundamentals/workflows/constructor-constraints/page.mdx": "2025-04-24T13:18:24.184Z",
   "app/learn/fundamentals/data-models/write-migration/page.mdx": "2025-07-23T15:32:18.008Z",