fix: unify theme system - fix theme switching persistence

- Unified localStorage key to 'theme-preference' across all components
- Fixed header.tsx using wrong localStorage key ('theme' instead of 'theme-preference')
- Added localStorage hybrid persistence for instant theme changes
- Removed router.refresh() which was causing stale data revert
- Replaced Blue theme with Sepia
- Consolidated auth() calls to prevent race conditions
- Updated UserSettingsData types to include all themes

keep-notes/app/(main)/admin/users/page.tsx

@@ -0,0 +1,29 @@
+import { getUsers } from '@/app/actions/admin'
+import { CreateUserDialog } from '../create-user-dialog'
+import { UserList } from '../user-list'
+import { Plus } from 'lucide-react'
+import { Button } from '@/components/ui/button'
+
+export default async function AdminUsersPage() {
+  const users = await getUsers()
+
+  return (
+    <div className="space-y-6">
+      <div className="flex justify-between items-center">
+        <div>
+          <h1 className="text-3xl font-bold text-gray-900 dark:text-white">
+            Users
+          </h1>
+          <p className="text-gray-600 dark:text-gray-400 mt-1">
+            Manage application users and permissions
+          </p>
+        </div>
+        <CreateUserDialog />
+      </div>
+
+      <div className="bg-white dark:bg-zinc-900 rounded-lg shadow overflow-hidden border border-gray-200 dark:border-gray-800">
+        <UserList initialUsers={users} />
+      </div>
+    </div>
+  )
+}