feat(1P): add state_class measurement to External CT Power sensor (#152)

External CT Power (register 172) had device_class: power but no state_class,
so Home Assistant kept no long-term statistics for it. Add state_class:
measurement to match the other power sensors.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: SupermotoJerry

pv_inverter/packages/deye_hybrid_1p/grid.yaml

@@ -266,6 +266,7 @@ sensor:
       - lambda: ${func_scale_ac_power}
     unit_of_measurement: "W"
     device_class: power
+    state_class: "measurement"
     accuracy_decimals: 0
     value_type: S_WORD
     icon: "mdi:transmission-tower"