feat: add ClockApp and SettingsPanel components with customizable settings

- Implemented ClockApp component to display time based on user settings.
- Created SettingsPanel for users to adjust clock type, time format, timezone, and theme.
- Added hooks for managing time, settings persistence, and fullscreen functionality.
- Introduced types for clock settings and themes, including default settings.
- Integrated URL parameter parsing for sharing clock configurations.
- Enhanced user experience with loading states and visual transitions.

src/app/error.tsx

@@ -0,0 +1,31 @@
+'use client';
+
+import { useEffect } from 'react';
+
+export default function Error({
+  error,
+  reset,
+}: {
+  error: Error & { digest?: string };
+  reset: () => void;
+}) {
+  useEffect(() => {
+    console.error(error);
+  }, [error]);
+
+  return (
+    <div className="min-h-screen flex flex-col items-center justify-center bg-slate-900 text-white p-4">
+      <h1 className="text-4xl font-bold text-red-500 mb-4">Oups !</h1>
+      <h2 className="text-xl font-semibold mb-4">Une erreur s&apos;est produite</h2>
+      <p className="text-slate-400 mb-8 text-center max-w-md">
+        Nous sommes désolés, quelque chose s&apos;est mal passé. Veuillez réessayer.
+      </p>
+      <button
+        onClick={reset}
+        className="px-6 py-3 bg-blue-500 text-white rounded-lg font-medium hover:bg-blue-600 transition-colors"
+      >
+        Réessayer
+      </button>
+    </div>
+  );
+}