feat: Add character names to scenarios and UI

Introduces `characterName` to the `Scenario` type, enabling AI personas to be explicitly named. This change also updates the `ScenarioCard` component to display the character name and adds foundational support for potential future scenario deletion functionality. The README has been updated with a new AI Studio link.

components/VoiceSession/VoiceHeader.tsx

@@ -0,0 +1,28 @@
+
+import React from 'react';
+import { PhoneOff, Flag } from 'lucide-react';
+
+interface VoiceHeaderProps {
+  title: string;
+  onExit: () => void;
+  onFinish: () => void;
+}
+
+const VoiceHeader: React.FC<VoiceHeaderProps> = ({ title, onExit, onFinish }) => (
+  <div className="p-8 flex justify-between items-center relative z-10">
+    <div className="flex items-center gap-4">
+      <button onClick={onExit} className="p-3 bg-white/5 hover:bg-white/10 rounded-2xl text-white/50 hover:text-white transition-all">
+        <PhoneOff size={20} />
+      </button>
+      <div>
+        <h2 className="text-white font-bold text-lg">{title}</h2>
+        <p className="text-teal-400 text-[10px] font-black uppercase tracking-widest">Active Roleplay Session</p>
+      </div>
+    </div>
+    <button onClick={onFinish} className="bg-teal-600 hover:bg-teal-700 text-white px-6 py-2.5 rounded-xl text-[10px] font-black uppercase tracking-widest transition-all shadow-lg shadow-teal-900/40 flex items-center gap-2">
+      <Flag size={14} /> Finish
+    </button>
+  </div>
+);
+
+export default React.memo(VoiceHeader);