Optimize web audio mic path: remove redundant copy and heap alloc

WebOnMic: drop intermediate Singles[] array, read PSingle directly.
PushAudio: replace per-frame SetLength/array of Byte with pre-allocated
FWsAudioBuf field — eliminates heap allocation from the DSP thread.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

WebServer.pas

@@ -172,6 +172,7 @@ type
     FOpusBuf:     array[0..OPUS_FRAME_SAMP-1] of Single;
     FOpusBufPos:  Integer;
     FOpusOut:     array[0..3999] of Byte;
+    FWsAudioBuf:  array[0..4000] of Byte;   // 1 байт типа + до 4000 байт Opus
     FOpusReady:   Boolean;
     // Opus decoder — для RX TX-mic аудио от браузера
     FOpusDec:        POpusDecoder;
@@ -1429,7 +1430,6 @@ procedure TWebServer.PushAudio(const Samples: PSingle; Count: Integer);
 var
   HasWs: Boolean;
   i, n, Enc: Integer;
-  Pkt: array of Byte;
 begin
   if not FRunning then Exit;
   FClientLock.Enter;
@@ -1454,10 +1454,9 @@ begin
                          @FOpusOut[0], SizeOf(FOpusOut));
       if Enc > 0 then
       begin
-        SetLength(Pkt, 1 + Enc);
-        Pkt[0] := WS_MSG_AUDIO;
-        Move(FOpusOut[0], Pkt[1], Enc);
-        BroadcastBinary(Pkt[0], Length(Pkt));
+        FWsAudioBuf[0] := WS_MSG_AUDIO;
+        Move(FOpusOut[0], FWsAudioBuf[1], Enc);
+        BroadcastBinary(FWsAudioBuf[0], 1 + Enc);
       end;
       FOpusBufPos := 0;
     end;