Fix: Change route from /admin to / to avoid Nextcloud conflicts

- Changed route URL from /admin to / (root path)
  - /admin was conflicting with Nextcloud built-in admin routes
  - Now uses apps/analyticshub/ instead
- Changed route name from admin#index to page#index
  - Follows Nextcloud naming conventions
- Updated info.xml navigation
  - Points to analyticshub.page.index
  - Removed <settings> section (can cause conflicts)
- Updated AdminController
  - Added request path to diagnostic output
  - Better styling for simple HTML page

The route was conflicting with Nextcloud's admin system.
New URL: https://teamworkapps.com/index.php/apps/analyticshub/

analyticshub/appinfo/routes.php

@@ -10,10 +10,10 @@ namespace OCA\AnalyticsHub;
 
 return [
     'routes' => [
-        // Admin route - simple GET only
+        // Admin route - use root path instead of /admin
         [
-            'name' => 'admin#index',
-            'url' => '/admin',
+            'name' => 'page#index',
+            'url' => '/',
             'verb' => 'GET',
             'requirements' => [],
         ],