fix(gateway-chat): honor UI endpoint/model/voice for TTS + standard-audio playback

The TTS path was hardwired to the parked zonos-gateway: it force-reverted the
endpoint field back to zonos :8890 on load, hardcoded model=ext-tts, and decoded
the response as Zonos-specific raw float32 PCM @ 44.1kHz. Result: quoted-text TTS
was dead once zonos was parked, and pointing the field elsewhere silently failed.

- Honor the interface: set endpoint/model/voice defaults only when a field is
  empty; never rewrite a user-typed value (removed the zonos auto-revert regex).
- Add a TTS model field (ttsModel); send the UI's model instead of hardcoding.
- Playback: request standard OpenAI /v1/audio/speech mp3 and decode via
  audioCtx.decodeAudioData (handles wav/mp3/ogg/flac from any endpoint).
- Defaults: endpoint = LiteLLM ext-tts alias (fleet TTS gateway), voice = nova.

tools/gateway-chat.html

@@ -67,11 +67,12 @@
       <div><label>Temperature</label><input id="temp" type="number" step="0.05" value="1"></div>
       <div><label>Max tokens</label><input id="max" type="number" step="1" value="1024"></div>
     </div>
-    <label style="margin-top:.5rem">🔊 ext-tts voice (quoted text)</label>
+    <label style="margin-top:.5rem">🔊 TTS (quoted text)</label>
     <label class="hint" style="display:flex;gap:.45rem;align-items:center;margin:.15rem 0"><input id="ttsOn" type="checkbox" style="width:auto"> Auto-play quoted dialogue</label>
-    <input id="ttsUrl" placeholder="http://10.100.79.3:8890/v1/audio/speech">
-    <input id="ttsVoice" placeholder="Cora">
-    <div class="hint">Settings persist locally. No <code>tools</code> field is ever sent. Reasoning models show their <code>reasoning_content</code> above the answer. With 🔊 on, quoted text in each reply auto-plays via <code>ext-tts</code> (Zonos, streamed direct from zonos-gateway).</div>
+    <input id="ttsUrl" placeholder="endpoint — http://10.250.50.70:4000/v1/audio/speech">
+    <input id="ttsModel" placeholder="model — ext-tts">
+    <input id="ttsVoice" placeholder="voice — nova">
+    <div class="hint">Settings persist locally. No <code>tools</code> field is ever sent. Reasoning models show their <code>reasoning_content</code> above the answer. With 🔊 on, quoted text auto-plays via the <b>endpoint + model + voice set above</b> (OpenAI <code>/v1/audio/speech</code>, mp3).</div>
   </aside>
   <main id="main">
     <div id="log"></div>
@@ -85,17 +86,15 @@
   </main>
 <script>
 const $ = id => document.getElementById(id);
-const cfg = ['base','key','model','sys','temp','max','ttsUrl','ttsVoice'];
+const cfg = ['base','key','model','sys','temp','max','ttsUrl','ttsModel','ttsVoice'];
 cfg.forEach(k => { const v = localStorage.getItem('gc_'+k); if (v !== null) $(k).value = v; });
 if (!$('base').value) $('base').value = 'http://10.250.50.70:4000/v1';
-// ext-tts default = zonos-gateway direct (streams; bypasses LiteLLM audio buffering). Migrate any stale
-// mOrpheus URL (:8299/:8210//tts) OR the LiteLLM URL (:4000) to the direct gateway, persisting so it sticks.
-if (!$('ttsUrl').value || /:(8299|8210)|\/tts(\/stream)?$|10\.250\.50\.70:4000/.test($('ttsUrl').value)){
-  $('ttsUrl').value = 'http://10.100.79.3:8890/v1/audio/speech'; localStorage.setItem('gc_ttsUrl', $('ttsUrl').value);
-}
-if (!$('ttsVoice').value || $('ttsVoice').value.trim() === 'baddy'){
-  $('ttsVoice').value = 'Cora'; localStorage.setItem('gc_ttsVoice', $('ttsVoice').value);
-}
+// TTS: honor whatever endpoint/model/voice the interface holds. Set a default ONLY when a field is
+// empty — never rewrite a value the user typed. Defaults: endpoint = the LiteLLM ext-tts alias (which
+// fronts the fleet TTS gateway), model = ext-tts, voice = nova (an OpenAI voice name the gateway aliases).
+if (!$('ttsUrl').value)   { $('ttsUrl').value   = 'http://10.250.50.70:4000/v1/audio/speech'; localStorage.setItem('gc_ttsUrl', $('ttsUrl').value); }
+if (!$('ttsModel').value) { $('ttsModel').value = 'ext-tts'; localStorage.setItem('gc_ttsModel', $('ttsModel').value); }
+if (!$('ttsVoice').value) { $('ttsVoice').value = 'nova';    localStorage.setItem('gc_ttsVoice', $('ttsVoice').value); }
 cfg.forEach(k => $(k).addEventListener('input', e => localStorage.setItem('gc_'+k, e.target.value)));
 // 🔊 auto-play toggle is a checkbox (persist .checked)
 $('ttsOn').checked = localStorage.getItem('gc_ttsOn') === '1';
@@ -150,7 +149,7 @@ function addMsg(who, cls){
 }
 function showErr(text){ const m = addMsg('error','err'); m.body.className = 'err'; m.body.textContent = text; }
 
-// --- mOrpheus TTS: streaming-decode auto-voice of quoted text (Web Audio, low TTFA) ---
+// --- TTS: auto-voice quoted text via the configured OpenAI /v1/audio/speech endpoint (Web Audio) ---
 let audioCtx = null;   // shared AudioContext
 let ttsGen = 0;        // generation counter — a newer reply's stream supersedes older ones
 let speechHead = 0;    // shared playback clock — sentences queue onto it back-to-back
@@ -166,45 +165,38 @@ function extractQuotes(text){
   while ((m = re.exec(text)) !== null){ const q = (m[1] || m[2] || '').trim(); if (q) out.push(q); }
   return out;
 }
-// stream ONE quoted section (whole, so intonation/prosody across it is preserved) and queue its
-// PCM onto the shared speechHead clock; resolves when its audio is fully received (it plays on
-// while the NEXT quote starts generating). Chunk by QUOTE, not sentence — per-sentence lost prosody.
-async function streamOne(sentence, mine){
-  // ext-tts via zonos-gateway (direct, streams — bypasses LiteLLM's audio buffering): ttsUrl is the full
-  // OpenAI /v1/audio/speech endpoint. The gateway relays Zonos's raw float32 PCM @ 44.1kHz — decode as
-  // little-endian float32 (NOT int16) at 44100 Hz. The Bearer header is sent but the gateway ignores it.
+// Speak ONE quoted section (whole, so prosody across it is preserved). Honors the endpoint, model and
+// voice set in the interface; requests standard OpenAI /v1/audio/speech mp3 and plays it via Web Audio.
+// decodeAudioData handles wav/mp3/ogg/flac, so this works with whatever the configured endpoint returns.
+async function speakOne(sentence, mine){
   const url = $('ttsUrl').value.trim().replace(/\/+$/,'');
   const res = await fetch(url, {
     method:'POST',
     headers:{ 'Content-Type':'application/json', 'Authorization':'Bearer ' + $('key').value },
-    body: JSON.stringify({ model: 'ext-tts', input: sentence, voice: ($('ttsVoice').value.trim() || 'Cora') })
+    body: JSON.stringify({
+      model: ($('ttsModel').value.trim() || 'ext-tts'),
+      input: sentence,
+      voice: ($('ttsVoice').value.trim() || 'nova'),
+      response_format: 'mp3'
+    })
   });
-  if (!res.ok || !res.body) return false;
-  const reader = res.body.getReader();
-  let leftover = new Uint8Array(0);
-  for(;;){
-    const { done, value } = await reader.read();
-    if (done || mine !== ttsGen) break;                 // stop if a newer reply took over
-    let bytes = new Uint8Array(leftover.length + value.length);
-    bytes.set(leftover); bytes.set(value, leftover.length);
-    const n = bytes.length - (bytes.length % 4);        // whole float32 samples only (ext-tts PCM)
-    leftover = bytes.slice(n);
-    if (!n) continue;
-    const dv = new DataView(bytes.buffer, 0, n), N = n / 4, f32 = new Float32Array(N);
-    for (let i = 0; i < N; i++) f32[i] = dv.getFloat32(i * 4, true);   // Zonos float32 PCM, little-endian
-    const abuf = audioCtx.createBuffer(1, N, 44100); abuf.getChannelData(0).set(f32);
-    const src = audioCtx.createBufferSource(); src.buffer = abuf; src.connect(audioCtx.destination);
-    if (speechHead < audioCtx.currentTime + 0.05) speechHead = audioCtx.currentTime + 0.05;  // underrun catch-up
-    src.start(speechHead); speechHead += abuf.duration; // queue back-to-back on the shared clock
-  }
+  if (!res.ok) return false;
+  const raw = await res.arrayBuffer();
+  if (mine !== ttsGen) return true;                     // a newer reply superseded this one
+  let abuf;
+  try { abuf = await audioCtx.decodeAudioData(raw); }
+  catch (e){ return false; }                            // non-audio body (e.g. error JSON) or unsupported codec
+  if (mine !== ttsGen) return true;
+  const src = audioCtx.createBufferSource(); src.buffer = abuf; src.connect(audioCtx.destination);
+  if (speechHead < audioCtx.currentTime + 0.05) speechHead = audioCtx.currentTime + 0.05;
+  src.start(speechHead); speechHead += abuf.duration;   // queue back-to-back on the shared clock
   return true;
 }
 async function speakQuotes(text, msg){
   if (!$('ttsOn').checked) return;
   const quotes = extractQuotes(text);
   if (!quotes.length) return;
-  // Streaming backend (zonos-gateway) → send ALL quoted dialogue as ONE streamed request;
-  // the stream itself is the incremental playback, so no per-quote chunking is needed.
+  // Send ALL quoted dialogue as ONE request to the configured endpoint (one clip = consistent prosody).
   const joined = quotes.join('  ');
   const tag = document.createElement('span'); tag.textContent = ' 🔊';
   tag.style.cursor = 'pointer'; tag.title = 'ext-tts — ' + quotes.length + ' quote(s), click to replay';
@@ -213,7 +205,7 @@ async function speakQuotes(text, msg){
     primeAudio(); if (audioCtx.state === 'suspended') await audioCtx.resume();
     speechHead = audioCtx.currentTime + 0.12;           // reset the shared clock for this reply
     if (mine !== ttsGen) return;
-    if (!(await streamOne(joined, mine))){ tag.textContent = ' 🔇'; return; }
+    if (!(await speakOne(joined, mine))){ tag.textContent = ' 🔇'; return; }
     if (mine === ttsGen) tag.textContent = ' 🔈';
   };
   tag.onclick = () => play().catch(() => tag.textContent = ' 🔇');