[FEAT] ARIA voce naturale (proxy TTS nexus-voice-ms) + toggle voce — Fase C

Porting voce TRPG/AllTax (ElevenLabs "Sarah") sull'ARIA chat NIS2:
- AiController::tts() + route POST /api/ai/tts: proxy same-origin a nexus-voice-ms
  (config VOICE_MS_URL=172.21.0.1:4215, voce TTS_VOICE_ID=EXAVITQu4vr4xnSDxMaL,
  eleven_turbo_v2_5). requireAuth, cache MP3 sha256 (sys_get_temp_dir/nis2-tts-cache),
  validazioni (text<=800, voice_id allowlist), stream audio/mpeg, 502 se upstream non-audio.
- common.js: speak(answer) dopo ogni risposta ARIA (voce discreta vol .55, markdown
  strip), toggle 🔊/🔇 nell'header (muto persistito localStorage nis2_aria_voice),
  autoplay best-effort.
Smoke: voice-ms da nis2-app HTTP 200 audio/mpeg 19KB; /api/ai/tts 401 senza auth.
Reachability OK (no allowlist VOX necessaria). Cache-buster common.js -> 20260624g.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

public/js/common.js

@@ -1014,6 +1014,42 @@ function switchLang(lang) {
             + "font-family:-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,sans-serif;";
         document.body.appendChild(panel);
 
+        // ── Voce ARIA naturale (TTS via /api/ai/tts → nexus-voice-ms) ─────────────
+        var ttsMuted = localStorage.getItem('nis2_aria_voice') === 'off';
+        var ttsAudio = null;
+        function _ttsPlain(s) {
+            return String(s || '')
+                .replace(/```[\s\S]*?```/g, ' ')
+                .replace(/!?\[([^\]]*)\]\([^)]*\)/g, '$1')
+                .replace(/[#*_>`|]/g, ' ')
+                .replace(/\s+/g, ' ').trim().slice(0, 800);
+        }
+        function speak(text) {
+            if (ttsMuted) return;
+            var clean = _ttsPlain(text);
+            if (!clean) return;
+            var tok = localStorage.getItem('nis2_access_token') || '';
+            fetch('/api/ai/tts', {
+                method: 'POST',
+                headers: { 'Content-Type': 'application/json', 'Authorization': tok ? ('Bearer ' + tok) : '' },
+                body: JSON.stringify({ text: clean })
+            }).then(function (r) { return r.ok ? r.blob() : null; })
+              .then(function (b) {
+                  if (!b || ttsMuted) return;
+                  try { if (ttsAudio) ttsAudio.pause(); } catch (e) {}
+                  ttsAudio = new Audio(URL.createObjectURL(b));
+                  ttsAudio.volume = 0.55;
+                  ttsAudio.play().catch(function () {}); // autoplay bloccato → silenzioso
+              }).catch(function () {});
+        }
+        function toggleVoice() {
+            ttsMuted = !ttsMuted;
+            localStorage.setItem('nis2_aria_voice', ttsMuted ? 'off' : 'on');
+            if (ttsMuted && ttsAudio) { try { ttsAudio.pause(); } catch (e) {} }
+            var vb = document.getElementById('ai-chat-voice');
+            if (vb) vb.textContent = ttsMuted ? '🔇' : '🔊';
+        }
+
         var STORAGE_KEY = 'nis2_ai_chat';
         var history = [];
         var pending = false; // ARIA sta elaborando una risposta (mostra indicatore "sta scrivendo")
@@ -1071,6 +1107,8 @@ function switchLang(lang) {
                 +   '<div style="display:flex;align-items:center;gap:8px;font-weight:600">'
                 +     '<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" style="vertical-align:-2px"><path d="M12 3l1.8 4.6L18.5 9.5l-4.7 1.9L12 16l-1.8-4.6L5.5 9.5l4.7-1.9L12 3z"/></svg> ARIA — Assistente NIS2'
                 +   '</div>'
+                +   '<button id="ai-chat-voice" aria-label="Attiva/disattiva voce" title="Voce ARIA" style="background:none;'
+                +   'border:none;color:#fff;font-size:15px;cursor:pointer;margin-right:2px">' + (ttsMuted ? '🔇' : '🔊') + '</button>'
                 +   '<button id="ai-chat-close" aria-label="Chiudi" style="background:none;'
                 +   'border:none;color:#fff;font-size:18px;cursor:pointer">&times;</button>'
                 + '</div>'
@@ -1106,6 +1144,8 @@ function switchLang(lang) {
                 +   '</button>'
                 + '</form>';
             document.getElementById('ai-chat-close').onclick = closePanel;
+            var _vb = document.getElementById('ai-chat-voice');
+            if (_vb) _vb.onclick = toggleVoice;
             document.getElementById('ai-chat-form').onsubmit = onSubmit;
             var inputEl = document.getElementById('ai-chat-input');
             if (inputEl) {
@@ -1165,6 +1205,7 @@ function switchLang(lang) {
                           || (resp && (resp.answer || resp.message || resp.text))
                           || 'ARIA non ha risposto. Riprova tra poco.';
                 history.push({ role: 'assistant', content: answer });
+                try { speak(answer); } catch (e2) {}   // voce naturale ARIA (se non mutata)
             } catch (e) {
                 history.push({
                     role: 'assistant',