Retain transcript messages and add MQTT publish diagnostics

stt-worker/Dockerfile

@@ -16,6 +16,8 @@ ENV LOG_LEVEL=INFO \
     MQTT_VAD_TOPIC=evs/+/vad_segment \
     MQTT_TRANSCRIPT_TOPIC_TEMPLATE=evs/{device_id}/transcript \
     MQTT_STT_ERROR_TOPIC_TEMPLATE=evs/{device_id}/stt_error \
+    STT_TRANSCRIPT_RETAIN=true \
+    STT_ERROR_RETAIN=false \
     STT_MODEL=small \
     STT_DEVICE=cpu \
     STT_COMPUTE_TYPE=int8 \