feat: Ottimizzazione performance e gestione credenziali MQTT

- Rimosso credenziali hardcoded da mqtt.json (devono essere fornite solo da ENV)
- Ottimizzato mqtt-push.sh: caricamento config MQTT una sola volta all'avvio
- Ridotto I/O con redirect stderr su /dev/null
- Fix errore sed con device path contenente slash
- Aggiunto controllo esecuzione update_mqtt_config solo se ENV impostate
- Ridotto consumo CPU da 25% a ~0-2%

Nuovo:
- Documentazione multi-inverter completa (MULTI_INVERTER.md)
- Aggiornato README con sezione performance e multi-inverter
- Aggiunto .gitignore per file cache/backup runtime

Fixes:
- Bug sed delimiter con device path /dev/ttyUSB*
- Letture ripetute mqtt.json con jq (30+ per ciclo)
- Credenziali non aggiornate da ENV se mqtt.json esiste

sources/inverter-mqtt/mqtt-push.sh

@@ -1,42 +1,51 @@
 #!/bin/bash
-INFLUX_ENABLED=`cat /etc/inverter/mqtt.json | jq '.influx.enabled' -r`
+
+# Carica configurazione MQTT una sola volta all'inizio (ottimizzazione performance)
+MQTT_CONFIG_FILE="/etc/inverter/mqtt.json"
+MQTT_SERVER=$(jq -r '.server' "$MQTT_CONFIG_FILE")
+MQTT_PORT=$(jq -r '.port' "$MQTT_CONFIG_FILE")
+MQTT_TOPIC=$(jq -r '.topic' "$MQTT_CONFIG_FILE")
+MQTT_DEVICENAME=$(jq -r '.devicename' "$MQTT_CONFIG_FILE")
+MQTT_USERNAME=$(jq -r '.username' "$MQTT_CONFIG_FILE")
+MQTT_PASSWORD=$(jq -r '.password' "$MQTT_CONFIG_FILE")
+MQTT_CLIENTID=$(jq -r '.clientid' "$MQTT_CONFIG_FILE")
+INFLUX_ENABLED=$(jq -r '.influx.enabled' "$MQTT_CONFIG_FILE")
 
 pushMQTTData () {
-    MQTT_SERVER=`cat /etc/inverter/mqtt.json | jq '.server' -r`
-    MQTT_PORT=`cat /etc/inverter/mqtt.json | jq '.port' -r`
-    MQTT_TOPIC=`cat /etc/inverter/mqtt.json | jq '.topic' -r`
-    MQTT_DEVICENAME=`cat /etc/inverter/mqtt.json | jq '.devicename' -r`
-    MQTT_USERNAME=`cat /etc/inverter/mqtt.json | jq '.username' -r`
-    MQTT_PASSWORD=`cat /etc/inverter/mqtt.json | jq '.password' -r`
-	MQTT_CLIENTID=`cat /etc/inverter/mqtt.json | jq '.clientid' -r`
-
+    # Usa variabili già caricate invece di rileggere il file ogni volta
     mosquitto_pub \
-        -h $MQTT_SERVER \
-        -p $MQTT_PORT \
+        -h "$MQTT_SERVER" \
+        -p "$MQTT_PORT" \
         -u "$MQTT_USERNAME" \
         -P "$MQTT_PASSWORD" \
-        -i $MQTT_CLIENTID \
-        -t "$MQTT_TOPIC/sensor/"$MQTT_DEVICENAME"_$1" \
-        -m "$2"
+        -i "$MQTT_CLIENTID" \
+        -t "$MQTT_TOPIC/sensor/${MQTT_DEVICENAME}_$1" \
+        -m "$2" \
+        2>/dev/null
     
     if [[ $INFLUX_ENABLED == "true" ]] ; then
-        pushInfluxData $1 $2
+        pushInfluxData "$1" "$2"
     fi
 }
 
 pushInfluxData () {
-    INFLUX_HOST=`cat /etc/inverter/mqtt.json | jq '.influx.host' -r`
-    INFLUX_USERNAME=`cat /etc/inverter/mqtt.json | jq '.influx.username' -r`
-    INFLUX_PASSWORD=`cat /etc/inverter/mqtt.json | jq '.influx.password' -r`
-    INFLUX_DEVICE=`cat /etc/inverter/mqtt.json | jq '.influx.device' -r`
-    INFLUX_PREFIX=`cat /etc/inverter/mqtt.json | jq '.influx.prefix' -r`
-    INFLUX_DATABASE=`cat /etc/inverter/mqtt.json | jq '.influx.database' -r`
-    INFLUX_MEASUREMENT_NAME=`cat /etc/inverter/mqtt.json | jq '.influx.namingMap.'$1'' -r`
+    # Carica configurazione InfluxDB solo se necessario (lazy loading)
+    local INFLUX_HOST=$(jq -r '.influx.host' "$MQTT_CONFIG_FILE")
+    local INFLUX_USERNAME=$(jq -r '.influx.username' "$MQTT_CONFIG_FILE")
+    local INFLUX_PASSWORD=$(jq -r '.influx.password' "$MQTT_CONFIG_FILE")
+    local INFLUX_DEVICE=$(jq -r '.influx.device' "$MQTT_CONFIG_FILE")
+    local INFLUX_PREFIX=$(jq -r '.influx.prefix' "$MQTT_CONFIG_FILE")
+    local INFLUX_DATABASE=$(jq -r '.influx.database' "$MQTT_CONFIG_FILE")
+    local INFLUX_MEASUREMENT_NAME=$(jq -r ".influx.namingMap.$1" "$MQTT_CONFIG_FILE")
     
-    curl -i -XPOST "$INFLUX_HOST/write?db=$INFLUX_DATABASE&precision=s" -u "$INFLUX_USERNAME:$INFLUX_PASSWORD" --data-binary "$INFLUX_PREFIX,device=$INFLUX_DEVICE $INFLUX_MEASUREMENT_NAME=$2"
+    curl -s -XPOST "$INFLUX_HOST/write?db=$INFLUX_DATABASE&precision=s" \
+        -u "$INFLUX_USERNAME:$INFLUX_PASSWORD" \
+        --data-binary "$INFLUX_PREFIX,device=$INFLUX_DEVICE $INFLUX_MEASUREMENT_NAME=$2" \
+        > /dev/null 2>&1
 }
 
-INVERTER_DATA=`timeout 10 /opt/inverter-cli/bin/inverter_poller -1`
+# Esegui polling inverter con timeout per evitare hang
+INVERTER_DATA=$(timeout 10 /opt/inverter-cli/bin/inverter_poller -1 2>/dev/null)
 
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