Add real replacement pages for Pages, Media Library, and Users (v2.6.0)

Completes the "skinned vs. replaced" conversion started with Posts —
every native list-table screen the user asked about now has a genuine
custom Vue page behind it instead of dark-themed CSS over the native
markup. All three follow the same pattern as Posts: own REST controller
in admin/src/Rest/, own Vue page matching the Comments layout, native
screen redirected away (direct visits too, not just the sidebar link),
gated by its own Settings toggle defaulting to on.

- Pages (PagesData.php + Pages.vue): same as Posts, parent page shown
  instead of categories. edit.php?post_type=page redirects; other post
  types untouched.
- Media Library (MediaData.php + Media.vue): thumbnail grid with type
  filters (Images/Audio/Video/Documents/Unattached). Replaces the
  browse/library experience only — media-new.php (the actual upload
  screen) is untouched, same reasoning as leaving the block editor
  alone for Posts/Pages.
- Users (UsersData.php + Users.vue): filterable by role. Deleting a
  user always reassigns their content to whoever performs the deletion
  rather than exposing WP core's reassign-or-delete-everything choice
  as a one-click action — deliberately simplified to avoid a surprising,
  highly destructive default. user-new.php untouched.

Verified live: Media's grid renders real thumbnails/dimensions/file
sizes with working filters and search; Users shows real accounts with
role filters and correctly hides delete for the current user; both
redirect correctly from their native URLs.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

app/vite.config.js

@@ -31,6 +31,9 @@ export default defineConfig({
         plugins: fileURLToPath(new URL('./src/entries/plugins.js', import.meta.url)),
         comments: fileURLToPath(new URL('./src/entries/comments.js', import.meta.url)),
         posts: fileURLToPath(new URL('./src/entries/posts.js', import.meta.url)),
+        pages: fileURLToPath(new URL('./src/entries/pages.js', import.meta.url)),
+        media: fileURLToPath(new URL('./src/entries/media.js', import.meta.url)),
+        users: fileURLToPath(new URL('./src/entries/users.js', import.meta.url)),
         'locked-feature': fileURLToPath(new URL('./src/entries/locked-feature.js', import.meta.url)),
       },
       output: {