fix: remove all unnecessary animations from all pages

- Remove dead code animations (animate-in, fade-in, slide-in, zoom-in, shake) from tailwindcss-animate plugin (not installed)
- Remove decorative transition effects (transition-all, transition-colors) from all page components
- Remove scale effects (active:scale-95) from buttons
- Remove bounce animations (animate-bounce) from icons
- Keep functional animate-spin on loading spinners as they provide essential loading feedback

Affected pages: Dashboard, Timestamp, Jwt, JsonTools, Base64Converter, HtmlToMarkdown, MarkdownToHtml, QrCode, TextStatistics

pages/Base64Converter/index.tsx

@@ -20,7 +20,7 @@ export default function Index() {
   );
 
   return (
-    <div className="p-4 w-full flex flex-col space-y-4 min-h-[520px] select-none animate-in fade-in duration-300">
+    <div className="p-4 w-full flex flex-col space-y-4 min-h-[520px] select-none">
       <SwitchButtonGroup
         value={pageMode}
         options={[