Name the AI persona "Альтушка Ирина"

Rename overlay/checkbox labels and update ai-prompt.txt so the AI
knows its own name.

server.js

@@ -305,8 +305,8 @@ io.on('connection', (socket) => {
             const aiMessageId = crypto.randomUUID();
             console.log(`[ai] streamer=${streamer.id} id=${aiMessageId} reply="${replyText}"`);
             broadcastMessage(
-              room, aiMessageId, replyText, '🤖 ИИ', durationMs,
-              `Ответ от ИИ. ${replyText}`,
+              room, aiMessageId, replyText, 'Альтушка Ирина 🤖', durationMs,
+              `Альтушка Ирина отвечает. ${replyText}`,
               AI_VOICE
             );
           })