li3: add Lithionics Li3 house battery BMS -> Home Assistant MQTT

Publishes the RV's 12V LiFePO4 house battery to HA via MQTT discovery
(pack voltage, 4 cell voltages, current, SOC, BMS/battery temp, status).
Connects over the battery's BLE HM-10 UART module (service ffe0/char
ffe1, no pairing) using bleak; protocol reverse-engineered from the
com.lithionics.bms Android app's own BLE/parsing code.

Deliberately named li3/ and van-li3-battery, not battery/van-battery —
that name is reserved for the host's own AC/UPS power-supply monitor
(different hardware, unrelated concern).

Self-heals a bluetoothd discovery-state wedge (Discovering stuck "yes",
connects failing with le-connection-abort-by-local) that shows up after
repeated failed connects to this device on the Pi's onboard adapter: the
daemon retries scan/connect internally (MQTT session and HA entities
stay up across retries) and restarts bluetooth.service itself after 3
consecutive scan failures, rate-limited to once per 5 min.

deploy.sh

@@ -188,6 +188,21 @@ python3 -c 'import gps' 2>/dev/null \
 python3 -c 'import paho.mqtt' 2>/dev/null \
     || warn "python3-paho-mqtt missing (apt install python3-paho-mqtt) — van-gps-owntracks won't start"
 
+echo "== li3 (RV house battery BMS -> MQTT/HA) =="
+# NOT the laptop's own AC/battery monitor — that's power/van-battery (different
+# hardware, different concern). This is the Lithionics Li3 12V LiFePO4 house
+# battery, over its BLE HM-10 UART module (no pairing) -> Home Assistant MQTT
+# discovery. Broker + creds live only on the system (0600, seeded from
+# li3/config.json.example — same pattern as gps/pushover).
+install -D -m0755 li3/van-li3-battery         /usr/local/sbin/van-li3-battery
+install -D -m0644 li3/van-li3-battery.service /etc/systemd/system/van-li3-battery.service
+if [ ! -f /etc/van-li3/config.json ]; then
+    install -D -m0600 li3/config.json.example /etc/van-li3/config.json
+    warn "seeded /etc/van-li3/config.json (EDIT IT: add MQTT username + password)"
+fi
+python3 -c 'import bleak' 2>/dev/null \
+    || warn "python3-bleak missing (apt install python3-bleak) — van-li3-battery won't start"
+
 echo "== thermal monitor =="
 install -D -m0755 power/van-thermal         /usr/local/sbin/van-thermal
 install -D -m0644 power/thermal-config.json /etc/van-thermal/config.json
@@ -236,7 +251,7 @@ systemctl restart systemd-resolved
 # its wait-online would just stall network-online.target. NM-wait-online covers WANs.
 systemctl mask systemd-networkd-wait-online.service >/dev/null 2>&1 || true
 systemctl unmask hostapd >/dev/null 2>&1 || true
-systemctl enable regdomain.service hostapd hostapd-2g van-ap-dnsmasq nftables systemd-networkd van-failover van-thermal van-nvme-watch van-ap-watchdog van-ap-watchdog-2g van-wlan-watchdog van-modem-watch van-gps-owntracks >/dev/null 2>&1 || true
+systemctl enable regdomain.service hostapd hostapd-2g van-ap-dnsmasq nftables systemd-networkd van-failover van-thermal van-nvme-watch van-ap-watchdog van-ap-watchdog-2g van-wlan-watchdog van-modem-watch van-gps-owntracks van-li3-battery >/dev/null 2>&1 || true
 # bluetooth: host BlueZ serves the onboard hci0 to the HA container over D-Bus
 systemctl enable --now bluetooth >/dev/null 2>&1 || true
 systemctl start homeassistant || warn "homeassistant failed to start (podman/quadlet — check journalctl -u homeassistant)"
@@ -245,6 +260,7 @@ systemctl start frigate || warn "frigate failed to start (podman/quadlet — che
 systemctl restart van-thermal
 systemctl restart van-nvme-watch
 systemctl restart van-gps-owntracks
+systemctl restart van-li3-battery
 # Pick up unmanaged-devices changes so NM releases/keeps the right interfaces.
 nmcli general reload 2>/dev/null || systemctl reload NetworkManager 2>/dev/null || true
 # restart in dependency order: bridge + members first, then hostapd enslaves the
@@ -270,3 +286,4 @@ echo "  iw dev $WIFI_2G_IFACE info | grep -E 'ssid|channel|width'"
 echo "  cat /run/van-failover/state.json"
 echo "  cat /run/van-thermal/state.json"
 echo "  cat /run/van-nvme-watch/state.json"
+echo "  journalctl -u van-li3-battery -n 20"