feat(sensors): labeled per-zone thermal layer in lmsensors-extend [#736]

Hosts opt in via /etc/snmp/lmsensors-zone-types (one zone type per
line, e.g. Jetson GPU-therm); each type renders its own zone-<type>
chip block so HA templates anchor on the chip name. Default behavior
unchanged; no snmpd restarts (extend re-execs per poll).

dcinfra/sensors/temper/lmsensors-extend.sh

@@ -134,6 +134,32 @@ format_sysfs_block() {
     done <<<"$input"
 }
 
+# Labeled per-zone temps (e.g. Jetson GPU-therm) [#736]. Hosts opt in by
+# listing zone types (one per line) in /etc/snmp/lmsensors-zone-types; no
+# snmpd.conf change or restart needed (extend re-execs per poll). Each type
+# renders its own chip block so HA templates can anchor on the chip name.
+ZONE_TYPES_FILE="${ZONE_TYPES_FILE:-/etc/snmp/lmsensors-zone-types}"
+
+format_labeled_zones() {
+    local z type mc want signed
+    [[ -r "$ZONE_TYPES_FILE" ]] || return 1
+    while IFS= read -r want; do
+        want="${want%%#*}"; want="${want//[[:space:]]/}"
+        [[ -n "$want" ]] || continue
+        for z in "$SYSFS_THERMAL_ROOT"/thermal_zone[0-9]*; do
+            [[ -r "$z/type" && -r "$z/temp" ]] || continue
+            [[ "$(<"$z/type")" == "$want" ]] || continue
+            mc="$(<"$z/temp")"
+            [[ "$mc" =~ ^-?[0-9]+$ ]] || continue
+            signed="$(awk -v mc="$mc" 'BEGIN { printf "%.1f", mc / 1000 }')"
+            signed="${signed#+}"
+            [[ "$signed" == -* ]] || signed="+$signed"
+            printf 'zone-%s-virtual-0\nAdapter: Virtual device\ntemp1:        %s°C\n\n' "$want" "$signed"
+        done
+    done <"$ZONE_TYPES_FILE"
+    return 0
+}
+
 main() {
     local out="" block internal external native="" sysinput
     if native="$(run_native_sensors)" && [[ -n "$native" ]]; then
@@ -155,6 +181,9 @@ main() {
        && block="$(format_sysfs_block "$sysinput")"; then
         out+="$block"$'\n'
     fi
+    if block="$(format_labeled_zones)" && [[ -n "$block" ]]; then
+        out+="$block"$'\n'
+    fi
     [[ -n "$out" ]] || {
         echo "error: no sensor sources available (lm-sensors pkg? TEMPer venv? sysfs thermal?)" >&2
         return 1