Fix: relay WebSocket messages as text frames (browsers got Blobs they could not parse)

Root cause of 'track does not start': the server re-broadcast incoming frames as
binary (Buffer), so the browser output page received Blobs, JSON.parse failed,
and every command (playTrack, etc.) was silently dropped — only the text-encoded
lastEffect sync got through. Broadcast as text now; net.js also handles Blob
defensively. Also: no-store for app assets + kiosk --disk-cache-size=1 so
redeploys always take effect; /api/clients debug endpoint; /api/peaks duration.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/js/net.js

@@ -14,11 +14,16 @@
     ws.onopen = () => { ready = true; setStatus(true); while (queue.length) ws.send(queue.shift()); };
     ws.onclose = () => { ready = false; setStatus(false); setTimeout(connect, 1000); }; // survive server restarts
     ws.onerror = () => { try { ws.close(); } catch (e) {} };
-    ws.onmessage = (ev) => {
-      let m; try { m = JSON.parse(ev.data); } catch (e) { return; }
+    const handle = (txt) => {
+      let m; try { m = JSON.parse(txt); } catch (e) { return; }
       if (m.ch === 'ctl') ctlCbs.forEach(cb => cb(m.msg));
       else if (m.ch === 'rpt') rptCbs.forEach(cb => cb(m.msg));
     };
+    ws.onmessage = (ev) => {
+      if (typeof ev.data === 'string') handle(ev.data);
+      else if (ev.data && typeof ev.data.text === 'function') ev.data.text().then(handle); // Blob
+      else handle(String(ev.data));
+    };
   }
   connect();