docs: refresh screenshots for the unified UI, add directory.png

Screenshots were still showing the pre-unification nav (Dashboard/Sites/
Integrations); replace with the current Users/Groups/Directory/Executive
shell and add a directory.png for the new consolidated inventory page.
Fix a couple of stale "Integrations page" / "Sites" references in the
concept docs to match.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

docs/oauth.md

@@ -64,6 +64,8 @@ Clients are managed directly from the **Directory** tab in the web UI. They are
 
 > All client-management actions use the standard Directory API (`/api/directory-admin/resources`) and are gated by the `app_sso_directory_admin` group.
 
+<a href="images/oauth-clients.png" target="_blank"><img src="images/oauth-clients.png" alt="Editing an OAuth client resource" width="80%"></a>
+
 ## Scopes
 
 | Scope | Claims / access |