feat(channel): echo voice audio transcription

pkg/config/config.go

@@ -58,6 +58,7 @@ type Config struct {
 	Tools     ToolsConfig     `json:"tools"`
 	Heartbeat HeartbeatConfig `json:"heartbeat"`
 	Devices   DevicesConfig   `json:"devices"`
+	Voice     VoiceConfig     `json:"voice"`
 }
 
 // MarshalJSON implements custom JSON marshaling for Config
@@ -424,6 +425,10 @@ type DevicesConfig struct {
 	MonitorUSB bool `json:"monitor_usb" env:"PICOCLAW_DEVICES_MONITOR_USB"`
 }
 
+type VoiceConfig struct {
+	EchoTranscription bool `json:"echo_transcription" env:"PICOCLAW_VOICE_ECHO_TRANSCRIPTION"`
+}
+
 type ProvidersConfig struct {
 	Anthropic     ProviderConfig       `json:"anthropic"`
 	OpenAI        OpenAIProviderConfig `json:"openai"`

pkg/config/defaults.go

@@ -461,5 +461,8 @@ func DefaultConfig() *Config {
 			Enabled:    false,
 			MonitorUSB: true,
 		},
+		Voice: VoiceConfig{
+			EchoTranscription: false,
+		},
 	}
 }