feat(sensors): sysfs thermal fallback + SBC fleet coverage [#341][#457][#458]

lm-sensors is silent on SBCs (Pis, Jetson-class), so the wrapper now falls
back to /sys/class/thermal zones rendered in lm-sensors format when native
sensors output is empty; suppressed when native output exists to avoid
duplicates. TDD: 3 new unit tests (12 green). Sensor stack deployed to
jetson + pfvsvrpi + 3 subopis (verified from poller), HA pack extended to
16 sensors across 14 hosts, high-temp automation covers the SBC fleet.

💘 Generated with Crush

Assisted-by: Crush:glm-5.2

dcinfra/ha/automations-ups-alerts.yaml

@@ -120,6 +120,11 @@
         - sensor.pfv_tsys6_cpu_temperature
         - sensor.pfv_tsys7_cpu_temperature
         - sensor.pfv_tsys9_cpu_temperature
+        - sensor.pfv_jetson_temperature
+        - sensor.pfv_svrpi_temperature
+        - sensor.pfv_subopi3_temperature
+        - sensor.pfv_subopi_dev_3_temperature
+        - sensor.pfv_subopi_dev_4_temperature
       above: 104
   actions:
     - action: notify.send_message

dcinfra/ha/sensors-snmp-plant.yaml

@@ -197,6 +197,82 @@ sensor:
       {% set m = value | regex_findall('Package id 0:\s*\+?(-?\d+\.?\d*)') %}
       {{ ((m | first | float * 9 / 5) + 32) | round(1) if m else 'unknown' }}
 
+  # --- SBC fleet (sysfs thermal fallback in lmsensors-extend v2; temp1 = zone0/SoC) ---
+  - platform: snmp
+    name: "PFV jetson temperature"
+    host: pfv-jetson-nano-1.knel.net
+    version: 2c
+    community: kn3lmgmt
+    baseoid: .1.3.6.1.4.1.8072.1.3.2.3.1.2.9.108.109.115.101.110.115.111.114.115
+    accept_errors: true
+    device_class: temperature
+    state_class: measurement
+    unit_of_measurement: "°F"
+    unique_id: pfv_jetson_temperature
+    value_template: >-
+      {% set m = value | regex_findall('temp1:\s*\+?(-?\d+\.?\d*)') %}
+      {{ ((m | first | float * 9 / 5) + 32) | round(1) if m else 'unknown' }}
+
+  - platform: snmp
+    name: "PFV svrpi temperature"
+    host: pfvsvrpi.knel.net
+    version: 2c
+    community: kn3lmgmt
+    baseoid: .1.3.6.1.4.1.8072.1.3.2.3.1.2.9.108.109.115.101.110.115.111.114.115
+    accept_errors: true
+    device_class: temperature
+    state_class: measurement
+    unit_of_measurement: "°F"
+    unique_id: pfv_svrpi_temperature
+    value_template: >-
+      {% set m = value | regex_findall('temp1:\s*\+?(-?\d+\.?\d*)') %}
+      {{ ((m | first | float * 9 / 5) + 32) | round(1) if m else 'unknown' }}
+
+  - platform: snmp
+    name: "PFV subopi3 temperature"
+    host: subopi3.knel.net
+    version: 2c
+    community: kn3lmgmt
+    baseoid: .1.3.6.1.4.1.8072.1.3.2.3.1.2.9.108.109.115.101.110.115.111.114.115
+    accept_errors: true
+    device_class: temperature
+    state_class: measurement
+    unit_of_measurement: "°F"
+    unique_id: pfv_subopi3_temperature
+    value_template: >-
+      {% set m = value | regex_findall('temp1:\s*\+?(-?\d+\.?\d*)') %}
+      {{ ((m | first | float * 9 / 5) + 32) | round(1) if m else 'unknown' }}
+
+  - platform: snmp
+    name: "PFV subopi-dev-3 temperature"
+    host: subopi-dev-3.knel.net
+    version: 2c
+    community: kn3lmgmt
+    baseoid: .1.3.6.1.4.1.8072.1.3.2.3.1.2.9.108.109.115.101.110.115.111.114.115
+    accept_errors: true
+    device_class: temperature
+    state_class: measurement
+    unit_of_measurement: "°F"
+    unique_id: pfv_subopi_dev_3_temperature
+    value_template: >-
+      {% set m = value | regex_findall('temp1:\s*\+?(-?\d+\.?\d*)') %}
+      {{ ((m | first | float * 9 / 5) + 32) | round(1) if m else 'unknown' }}
+
+  - platform: snmp
+    name: "PFV subopi-dev-4 temperature"
+    host: subopi-dev-4.knel.net
+    version: 2c
+    community: kn3lmgmt
+    baseoid: .1.3.6.1.4.1.8072.1.3.2.3.1.2.9.108.109.115.101.110.115.111.114.115
+    accept_errors: true
+    device_class: temperature
+    state_class: measurement
+    unit_of_measurement: "°F"
+    unique_id: pfv_subopi_dev_4_temperature
+    value_template: >-
+      {% set m = value | regex_findall('temp1:\s*\+?(-?\d+\.?\d*)') %}
+      {{ ((m | first | float * 9 / 5) + 32) | round(1) if m else 'unknown' }}
+
 # ---------------------------------------------------------------------------
 # PLACEHOLDERS — enable after dependencies land (do not invent OIDs live):
 #