refactor: remove unused pages and components, streamline Admin and Dashboard functionality

src/components/sidebar/AppSidebar.tsx

@@ -9,7 +9,7 @@ import {
   useSidebar,
 } from '@/components/ui/sidebar'
 import { useAuth } from '@/hooks/use-auth'
-import { Activity, Home, Users, Volume2, Settings } from 'lucide-react'
+import { Home, Users, Volume2, Settings } from 'lucide-react'
 import { Link, useLocation } from 'react-router'
 import { NavUser } from './NavUser'
 import { NavPlan } from './NavPlan'
@@ -25,19 +25,9 @@ const navigationItems = [
     href: '/soundboard',
     icon: Volume2,
   },
-  {
-    title: 'Activity',
-    href: '/activity',
-    icon: Activity,
-  },
 ]
 
 const adminNavigationItems = [
-  {
-    title: 'Users',
-    href: '/admin/users',
-    icon: Users,
-  },
   {
     title: 'Sounds',
     href: '/admin/sounds',