feat: add multilingual TTS selector (UI ready, EN working)

app.js

@@ -58,6 +58,11 @@ document.addEventListener("DOMContentLoaded", function() {
 window.ttsEnabled = false;
 window.lastSpokenText = "";
 
+window.ttsLang = 'en-US';
+window.setLang = function(lang) {
+    window.ttsLang = lang;
+    window.speechSynthesis.cancel();
+};
 window.toggleTTS = function() {
     window.ttsEnabled = !window.ttsEnabled;
     const btn = document.getElementById("tts-btn");
@@ -95,6 +100,10 @@ window.speakText = function(text) {
     function speakNext() {
         if (i >= chunks.length || !window.ttsEnabled) return;
         const utt = new SpeechSynthesisUtterance(chunks[i].trim());
+        utt.lang = window.ttsLang;
+        const voices = window.speechSynthesis.getVoices();
+        const match = voices.find(v => v.lang === window.ttsLang);
+        if (match) utt.voice = match;
         utt.rate = 0.95;
         utt.pitch = 1.0;
         utt.volume = 1.0;

index.html

@@ -375,6 +375,13 @@
         <button class="theme-btn" id="theme-btn" onclick="toggleTheme()" title="Toggle light/dark theme">🌙</button>
         <button id="tts-btn" class="tts-btn" onclick="toggleTTS()" title="Voice OFF — click to enable">🔊 Voice</button>
         <button class="tts-btn" onclick="replayLast()" title="Replay last response">🔁 Replay</button>
+        <select id="lang-select" class="header-btn" onchange="setLang(this.value)" title="TTS Language">
+          <option value="en-US">🇺🇸 EN</option>
+          <option value="hi-IN">🇮🇳 HI</option>
+          <option value="ta-IN">🇮🇳 TA</option>
+          <option value="te-IN">🇮🇳 TE</option>
+          <option value="ar-SA">🇸🇦 AR</option>
+        </select>
         <button id="export-btn" class="header-btn" title="Export chat as Markdown">
           📥 Export
         </button>