feat(dashboard): live TTS voice controls (speed/word-gap/sentence-gap/pitch)

Adds a "봇 목소리(TTS) 조절" panel to the voice-server dashboard so the four
controls can be tuned from the browser instead of only via env vars:

- 4 sliders (glyph speed, word gap, sentence gap, pitch) with live labels
- 미리듣기: synthesises a sample with the slider values WITHOUT changing the
  live bot voice (new per-call overrides on MeloTTS.synth)
- 봇에 적용: commits the slider values to the live TTS instance; next reply uses
  them. 기본값 button resets to the manual defaults.

Backend: GET/POST /api/tts/settings (clamped to the manual ranges) and POST
/api/tts/preview (returns audio/wav). Panel shows only when tts is a real
(non-mock) backend.

Verified end-to-end against a live dashboard instance: page renders the panel,
GET returns defaults, POST applies+clamps (pitch 99->12), preview returns a
valid wav and leaves the live settings unchanged; 29 tests pass.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

wsai/dashboard.py

@@ -83,6 +83,8 @@ def _make_handler(dash: "Dashboard"):
                 q = _up.parse_qs(self.path.split("?", 1)[1] if "?" in self.path else "")
                 gid = (q.get("guildId", [""])[0])
                 self._send_json({"ok": True, "guildId": gid, "lists": dash.bot.get_lists(gid)})
+            elif path == "/api/tts/settings":
+                self._handle_tts_settings_get()
             elif path == "/events":
                 self._stream_events()
             else:
@@ -109,6 +111,10 @@ def _make_handler(dash: "Dashboard"):
                 self._handle_bot_select()
             elif path == "/api/bot/lists":
                 self._handle_bot_lists()
+            elif path == "/api/tts/settings":
+                self._handle_tts_settings_post()
+            elif path == "/api/tts/preview":
+                self._handle_tts_preview()
             else:
                 self._send(404, b"not found", "text/plain; charset=utf-8")
 
@@ -276,6 +282,54 @@ def _make_handler(dash: "Dashboard"):
             monitor.log("info", f"청취 화이트/블랙리스트 업데이트 (guild={guild_id})")
             self._send_json({"ok": True, "guildId": guild_id, "lists": saved})
 
+        def _handle_tts_settings_get(self) -> None:
+            """Return the live TTS controls (speed/word_gap/sentence_gap/pitch)
+            and their slider ranges so the page can render the panel."""
+            if dash.tts is None:
+                self._send_json({"ok": False, "error": "TTS not enabled"}, 503)
+                return
+            self._send_json(dash.tts_settings())
+
+        def _handle_tts_settings_post(self) -> None:
+            """Apply new TTS controls to the live bot voice (next reply uses them)."""
+            if dash.tts is None:
+                self._send_json({"ok": False, "error": "TTS not enabled"}, 503)
+                return
+            raw = self._read_body()
+            try:
+                data = json.loads(raw.decode("utf-8")) if raw else {}
+            except (ValueError, AttributeError):
+                self._send_json({"ok": False, "error": "invalid JSON"}, 400)
+                return
+            res = dash.set_tts_settings(data)
+            monitor.log("info", "봇 목소리 파라미터 적용: "
+                        + json.dumps(res["settings"], ensure_ascii=False))
+            self._send_json(res)
+
+        def _handle_tts_preview(self) -> None:
+            """Synthesize a short sample with the supplied controls WITHOUT
+            changing the live bot voice, and return the wav for playback."""
+            if dash.tts is None:
+                self._send_json({"ok": False, "error": "TTS not enabled"}, 503)
+                return
+            raw = self._read_body()
+            try:
+                data = json.loads(raw.decode("utf-8")) if raw else {}
+                text = (data.get("text") or "").strip()
+            except (ValueError, AttributeError):
+                self._send_json({"ok": False, "error": "invalid JSON"}, 400)
+                return
+            if not text:
+                self._send_json({"ok": False, "error": "text required"}, 400)
+                return
+            try:
+                wav = dash.tts_preview(text, data)
+            except Exception as exc:  # noqa: BLE001 — surface the reason to the page
+                log.exception("TTS preview failed")
+                self._send_json({"ok": False, "error": f"{type(exc).__name__}: {exc}"}, 500)
+                return
+            self._send(200, wav, "audio/wav")
+
         def _handle_log_mutate(self, action: str) -> None:
             """Per-line log delete/edit by event id."""
             raw = self._read_body()
@@ -397,6 +451,60 @@ class Dashboard:
         if self.tts is not None:
             self._submit(self.tts._ensure())
 
+    # -- TTS voice controls (dashboard sliders) -------------------------- #
+    # (min, max, step) for each slider — mirrors the tts_site manual ranges.
+    _TTS_RANGES = {
+        "speed": (0.5, 2.0, 0.05),
+        "word_gap": (-0.2, 0.5, 0.01),
+        "sentence_gap": (-0.5, 1.5, 0.05),
+        "pitch": (-12.0, 12.0, 1.0),
+    }
+
+    def _tts_values(self) -> dict:
+        t = self.tts
+        return {
+            "speed": float(getattr(t, "speed", 1.25)),
+            "word_gap": float(getattr(t, "word_gap", 0.25)),
+            "sentence_gap": float(getattr(t, "sentence_gap", 0.75)),
+            "pitch": float(getattr(t, "pitch", 0.0)),
+        }
+
+    def tts_settings(self) -> dict:
+        return {"ok": True, "settings": self._tts_values(),
+                "ranges": {k: list(v) for k, v in self._TTS_RANGES.items()}}
+
+    def set_tts_settings(self, data: dict) -> dict:
+        """Clamp and apply provided controls to the live TTS instance."""
+        for key, (lo, hi, _step) in self._TTS_RANGES.items():
+            v = data.get(key)
+            if v is not None:
+                setattr(self.tts, key, float(max(lo, min(hi, float(v)))))
+        return self.tts_settings()
+
+    def _tts_overrides(self, data: dict) -> dict:
+        out = {}
+        for key, (lo, hi, _step) in self._TTS_RANGES.items():
+            v = data.get(key)
+            if v is not None:
+                out[key] = float(max(lo, min(hi, float(v))))
+        return out
+
+    def tts_preview(self, text: str, data: dict | None = None) -> bytes:
+        """Synthesize `text` with per-call control overrides (no change to the
+        live bot voice) and return the wav bytes."""
+        import os
+        if self.tts is None:
+            raise RuntimeError("TTS not enabled")
+        overrides = self._tts_overrides(data or {})
+        out_path = self._submit(self.tts.synth(text, **overrides))
+        with open(out_path, "rb") as f:
+            wav = f.read()
+        try:
+            os.remove(out_path)
+        except OSError:
+            pass
+        return wav
+
     def voice_turn(self, audio_bytes: bytes, speaker: str = "",
                    guild: str = "", channel: str = "") -> dict:
         """One Discord voice turn: decode the uploaded utterance, recognise it
@@ -621,6 +729,11 @@ PAGE = r"""<!DOCTYPE html>
   .btn.rec{background:#4a1f27;border-color:#7a2531;color:#ffb3bb}
   .sttstat{color:var(--muted);font-size:12.5px}
   .sttres{margin-top:12px;font-size:15px;min-height:1px}
+  .ttsgrid{display:grid;grid-template-columns:repeat(auto-fit,minmax(210px,1fr));gap:12px 18px;margin:2px 0 12px}
+  .ttsgrid label{display:flex;flex-direction:column;gap:6px;font-size:12.5px;color:var(--muted)}
+  .ttsgrid label b{color:var(--fg);font-weight:600}
+  .ttsgrid input[type=range]{width:100%;accent-color:#3aa0ff}
+  .ttstext{flex:1;min-width:180px;background:#0f2333;border:1px solid #234a63;color:var(--fg);border-radius:10px;padding:8px 12px;font-size:13px}
   .sttres .txt{color:var(--heard);font-weight:600;line-height:1.5}
   .sttres .meta{color:var(--muted);font-size:12px;margin-top:5px}
   .hbtn{padding:6px 12px;font-size:12.5px}
@@ -751,6 +864,27 @@ PAGE = r"""<!DOCTYPE html>
     </div>
     <div id="sttres" class="sttres"></div>
   </section>
+  <section class="sttbox" id="ttsbox" style="display:none">
+    <h2>🔊 봇 목소리(TTS) 조절 · MeloTTS</h2>
+    <div class="ttsgrid">
+      <label>글자 속도 <b id="tvSpeed">1.25x</b>
+        <input type="range" id="tSpeed" min="0.5" max="2.0" step="0.05" value="1.25"></label>
+      <label>단어 간격 <b id="tvWord">250 ms</b>
+        <input type="range" id="tWord" min="-0.2" max="0.5" step="0.01" value="0.25"></label>
+      <label>문장 간격 <b id="tvSent">0.75 s</b>
+        <input type="range" id="tSent" min="-0.5" max="1.5" step="0.05" value="0.75"></label>
+      <label>피치 <b id="tvPitch">0 반음</b>
+        <input type="range" id="tPitch" min="-12" max="12" step="1" value="0"></label>
+    </div>
+    <div class="sttrow">
+      <input id="tText" class="ttstext" placeholder="미리들을 문장" value="안녕하세요, 목소리 미리듣기입니다.">
+      <button id="tPreview" class="btn">▶ 미리듣기</button>
+      <button id="tApply" class="btn">💾 봇에 적용</button>
+      <button id="tReset" class="btn hbtn">기본값</button>
+      <span id="tStat" class="sttstat">슬라이더로 조절 → 미리듣기로 확인 → 봇에 적용하면 다음 답변부터 반영됩니다.</span>
+    </div>
+    <audio id="tAudio" controls style="display:none;margin-top:10px;width:100%"></audio>
+  </section>
   <div class="demobar" id="demobar" style="display:none"></div>
   <div class="comp" id="comp"></div>
   <div class="tfilter" id="tfilter">
@@ -839,6 +973,9 @@ function renderStatus(s){
   // replayed sample data, not a real conversation. Say so loudly.
   const sttReal = comps.stt && comps.stt!=='mock' && comps.stt!=='none';
   $('sttbox').style.display = sttReal ? 'block' : 'none';
+  const ttsReal = comps.tts && comps.tts!=='mock' && comps.tts!=='none';
+  $('ttsbox').style.display = ttsReal ? 'block' : 'none';
+  if(ttsReal) initTts();
   const mockParts = ['stt','brain','tts'].filter(k => comps[k]==='mock');
   const bar = $('demobar');
   if(mockParts.length){
@@ -1030,6 +1167,58 @@ async function sendBlob(blob){
   };
 })();
 
+// --- 봇 목소리(TTS) 조절: 슬라이더 → 미리듣기 → 봇 적용 -------------------- #
+let ttsInited = false;
+function ttsLabels(){
+  const sp=parseFloat($('tSpeed').value), wg=parseFloat($('tWord').value),
+        sg=parseFloat($('tSent').value), pt=parseInt($('tPitch').value,10);
+  $('tvSpeed').textContent = sp.toFixed(2)+'x';
+  $('tvWord').textContent  = Math.round(wg*1000)+' ms';
+  $('tvSent').textContent  = sg.toFixed(2)+' s';
+  $('tvPitch').textContent = (pt>0?'+'+pt:pt)+' 반음';
+}
+function ttsVals(){
+  return {speed:parseFloat($('tSpeed').value), word_gap:parseFloat($('tWord').value),
+          sentence_gap:parseFloat($('tSent').value), pitch:parseInt($('tPitch').value,10)};
+}
+function ttsSet(s){
+  if(!s) return;
+  $('tSpeed').value=s.speed; $('tWord').value=s.word_gap;
+  $('tSent').value=s.sentence_gap; $('tPitch').value=s.pitch; ttsLabels();
+}
+async function initTts(){
+  if(ttsInited) return; ttsInited = true;
+  ['tSpeed','tWord','tSent','tPitch'].forEach(id => $(id).addEventListener('input', ttsLabels));
+  $('tPreview').onclick = async ()=>{
+    const text=($('tText').value||'').trim();
+    if(!text){ $('tStat').textContent='미리들을 문장을 입력하세요.'; return; }
+    $('tStat').textContent='합성 중…';
+    try{
+      const r=await fetch('/api/tts/preview',{method:'POST',headers:{'Content-Type':'application/json'},
+        body:JSON.stringify(Object.assign({text},ttsVals()))});
+      if(!r.ok){ $('tStat').textContent='미리듣기 실패: '+(await r.text()); return; }
+      const blob=await r.blob(); const a=$('tAudio');
+      a.src=URL.createObjectURL(blob); a.style.display='block'; a.play();
+      $('tStat').textContent='미리듣기 재생 중 (봇에는 아직 미적용).';
+    }catch(e){ $('tStat').textContent='미리듣기 오류: '+e; }
+  };
+  $('tApply').onclick = async ()=>{
+    try{
+      const r=await fetch('/api/tts/settings',{method:'POST',headers:{'Content-Type':'application/json'},
+        body:JSON.stringify(ttsVals())});
+      const j=await r.json();
+      if(j.ok){ ttsSet(j.settings); toast('봇 목소리에 적용됨 · 다음 답변부터 반영'); }
+      else { $('tStat').textContent='적용 실패: '+(j.error||''); }
+    }catch(e){ $('tStat').textContent='적용 오류: '+e; }
+  };
+  $('tReset').onclick = ()=>{ ttsSet({speed:1.25,word_gap:0.25,sentence_gap:0.75,pitch:0});
+    $('tStat').textContent='기본값으로 되돌림 (미리듣기/적용을 눌러 반영).'; };
+  try{
+    const j=await (await fetch('/api/tts/settings')).json();
+    if(j.ok) ttsSet(j.settings);
+  }catch(e){}
+}
+
 // --- Reusable popup/modal (프롬프트, 화이트/블랙리스트 등이 공유) ---------- #
 function openModal(title, actionsHtml){
   $('modalTitle').textContent = title;