Remove duplicate GUI voice encoding and keep shared worker codec

tools/chatgui/src/voicemessageencoder.h

@@ -1,16 +1,11 @@
 #pragma once
 
 #include <QString>
-#include <cstdint>
 
 class VoiceEncoder {
 public:
     static void setPreset(int preset);
     static int preset();
 
-    static int encodeToFile(const int16_t* pcm, size_t pcmCount, int sampleRate, int channels,
-                            const QString& filePath, float& outDurationSec);
-    static QString generateFileName();
-    static QString mediaDir(const QString& dbPath, const QString& channelId);
     static void ensureMediaDir(const QString& dir);
 };