fix: change execution mode

src/components/buttons/ThemeToggleButton.astro

@@ -43,13 +43,12 @@
 </button>
 
 <script is:inline>
-  const applyTheme = () => {
+  (() => {
     const isDark =
       localStorage.theme === 'dark' ||
       (!('theme' in localStorage) && window.matchMedia('(prefers-color-scheme: dark)').matches);
     document.documentElement.classList.toggle('dark', isDark);
-  };
-  applyTheme();
+  })();
 </script>
 
 <script>