SAFETY-118: read the peak forecast in its own unit

peak_forecast_entity is read through pv.watts() by its unit_of_measurement;
the abs(raw) < 50 size rule is gone. No unit or a non-power unit means the
forecast is not used, with one warning per cause. The validator no longer
claims a kW sensor is taken as watts for this entity.

Co-Authored-By: Claude <noreply@anthropic.com>

goodwe_controller/app/uilayout.py

@@ -194,7 +194,7 @@ GROUPS = (
             Field("peak_cap_w", SLIDER, "kW", scale=1000, step=100,
                   simple=True, wizard=5, note="month_peak"),
             Field("peak_margin_w", SLIDER, "W", step=10),   # SAFETY-79
-            Field("peak_forecast_entity", ENTITY, kind="power_w", wizard=5),
+            Field("peak_forecast_entity", ENTITY, kind="power", wizard=5),
             Field("peak_soc_floor", LOCKED, "%"),
         )),
         Part("start", (