fix: ScriptProcessorNode fallback + worklet process() logging

- ScriptProcessorNode fallback khi AudioWorkletNode fails
- Render trực tiếp trong onaudioprocess callback, không cần setInterval
- Worklet log peak + queue depth mỗi 50 process() calls
- Log audioCtx state + sampleRate khi init

app/static/js/worklets/fluidsynth-bridge.js

@@ -3,6 +3,7 @@ class FluidSynthBridge extends AudioWorkletProcessor {
     super();
     this.leftQ = [];
     this.rightQ = [];
+    this.called = 0;
     this.port.onmessage = (e) => {
       const d = e.data;
       if (d.type === 'PCM') {
@@ -15,6 +16,7 @@ class FluidSynthBridge extends AudioWorkletProcessor {
   process(inputs, outputs) {
     const out = outputs[0];
     if (!out) return true;
+    this.called++;
     const len = out[0].length;
     const qL = this.leftQ;
     const qR = this.rightQ;
@@ -28,6 +30,14 @@ class FluidSynthBridge extends AudioWorkletProcessor {
       if (si >= qL[fi].length) { fi++; si = 0; }
     }
     if (fi > 0) { this.leftQ.splice(0, fi); this.rightQ.splice(0, fi); }
+    if (this.called % 50 === 0) {
+      var pk = 0;
+      for (var j = 0; j < len; j++) {
+        var v = out[0][j] > 0 ? out[0][j] : -out[0][j];
+        if (v > pk) pk = v;
+      }
+      if (pk > 0) console.log('[FluidSynth:bridge] process #' + this.called + ' peak:' + pk.toFixed(6) + ' q:' + qL.length);
+    }
     return true;
   }
 }