fix: RMS mic level, 25ms timer, speaker test, overlay recording indicator

- AudioRecorder: peak replaced with RMS (sqrt mean of squares)
- AudioDeviceSettings: level meter timer 100ms -> 25ms
- SoundManager: playRawPcm uses ma_audio_buffer_ref instead of ma_decoder (fixes speaker test)
- InputBar: recording overlay positioned over text input, no layout shift
- messagelist: removed old recording indicator widget

tools/chatgui/src/sound_manager.cpp

@@ -143,21 +143,21 @@ ma_context* SoundManager::context() {
 void SoundManager::playRawPcm(const int16_t* pcm, int sampleCount, int sampleRate, int channels) {
     if (!m_engine || !m_initialized) return;
 
-    ma_decoder_config decCfg = ma_decoder_config_init(ma_format_s16, (ma_uint32)channels, (ma_uint32)sampleRate);
-    ma_decoder* decoder = new ma_decoder;
-    ma_result r = ma_decoder_init_memory(pcm, (ma_uint64)sampleCount * channels * sizeof(int16_t), &decCfg, decoder);
+    ma_audio_buffer_ref* ref = new ma_audio_buffer_ref;
+    ma_result r = ma_audio_buffer_ref_init(ma_format_s16, (ma_uint32)channels,
+                                            pcm, (ma_uint64)sampleCount, ref);
     if (r != MA_SUCCESS) {
-        qWarning("SoundManager: PCM decoder init failed (%d)", r);
-        delete decoder;
+        qWarning("SoundManager: audio_buffer_ref_init failed (%d)", r);
+        delete ref;
         return;
     }
 
     ma_sound* sound = new ma_sound;
-    r = ma_sound_init_from_data_source(m_engine, (ma_data_source*)decoder, 0, nullptr, sound);
+    r = ma_sound_init_from_data_source(m_engine, (ma_data_source*)ref, 0, nullptr, sound);
     if (r != MA_SUCCESS) {
         qWarning("SoundManager: PCM sound init failed (%d)", r);
-        ma_decoder_uninit(decoder);
-        delete decoder;
+        ma_audio_buffer_ref_uninit(ref);
+        delete ref;
         delete sound;
         return;
     }
@@ -165,8 +165,6 @@ void SoundManager::playRawPcm(const int16_t* pcm, int sampleCount, int sampleRat
     ma_sound_set_volume(sound, m_volume);
     ma_sound_start(sound);
     qDebug("SoundManager: playing PCM (%d samples, %dHz, %dch)", sampleCount, sampleRate, channels);
-
-    /* auto-cleanup after playback ends. Note: decoder+sound leak on early shutdown, acceptable for voice messages */
 }
 
 QVector<SoundManager::DeviceInfo> SoundManager::enumeratePlaybackDevices() {