Implement proactive forecast-driven car charging strategy

- Replace reactive export-threshold wallbox activation with proactive
  logic: WallboxA/B activate when forecast ≥ mid AND PV ≥ threshold
  AND SOC ≥ 35%, without requiring grid export surplus
- Add WallboxB no-car detection via grid-delta probe (no PM available):
  after probe window, if grid shift < GridDeltaThreshW → no car, retry
  after configured timeout
- Add EOD soft stop: after 16:00, stop proactive car charging if
  remaining PV estimate can't cover battery deficit to 90% by sunset
- WW boost no longer requires export threshold; dynamic setpoint uses
  tank top temp + hysteresis + boost delta, capped at 60°C
- Proactive wallboxes bypass import-hysteresis shutdown; SOC emergency
  brake uses SOCFloor (5%) instead of standard AllConsumers gate
- Add WWTopTempC to SystemState (ww_top_temp metric from DHW cylinder)
- Add BatteryConfig (capacity_kwh), CarChargingConfig to config
- Add WWMaxSetpointC, WWHysteresisC to StrategicConfig
- Update Decide() signature: forecastKWh + sunsetTime parameters
- Update all tests; add proactive charging test cases

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/config/config.go

@@ -10,18 +10,43 @@ import (
 
 // Config is the top-level EMS configuration.
 type Config struct {
-	Prometheus PrometheusConfig      `yaml:"prometheus"`
-	Shelly     ShellyConfig          `yaml:"shelly"`
-	Viessmann  ViessmannConfig       `yaml:"viessmann"`
-	SOC        SOCThresholds         `yaml:"soc_thresholds"`
-	Hysteresis HysteresisConfig      `yaml:"hysteresis"`
-	Thresholds PowerThresholds       `yaml:"thresholds"`
-	Consumers  ConsumersConfig       `yaml:"consumers"`
-	Strategic  StrategicConfig       `yaml:"strategic"`
-	Season     SeasonConfig          `yaml:"season"`
-	Forecast   ForecastConfig        `yaml:"forecast"`
-	Cars       map[string]CarProfile `yaml:"cars"`
-	EMS        EMSConfig             `yaml:"ems"`
+	Prometheus  PrometheusConfig      `yaml:"prometheus"`
+	Shelly      ShellyConfig          `yaml:"shelly"`
+	Viessmann   ViessmannConfig       `yaml:"viessmann"`
+	SOC         SOCThresholds         `yaml:"soc_thresholds"`
+	Hysteresis  HysteresisConfig      `yaml:"hysteresis"`
+	Thresholds  PowerThresholds       `yaml:"thresholds"`
+	Consumers   ConsumersConfig       `yaml:"consumers"`
+	Strategic   StrategicConfig       `yaml:"strategic"`
+	Season      SeasonConfig          `yaml:"season"`
+	Forecast    ForecastConfig        `yaml:"forecast"`
+	Battery     BatteryConfig         `yaml:"battery"`
+	CarCharging CarChargingConfig     `yaml:"car_charging"`
+	Cars        map[string]CarProfile `yaml:"cars"`
+	EMS         EMSConfig             `yaml:"ems"`
+}
+
+// BatteryConfig holds physical battery properties.
+type BatteryConfig struct {
+	CapacityKWh float64 `yaml:"capacity_kwh"` // usable battery capacity in kWh
+}
+
+// CarChargingConfig holds parameters for the proactive car charging strategy.
+type CarChargingConfig struct {
+	MinSOC           int     `yaml:"min_soc"`             // minimum SOC% to start car charging (e.g. 35)
+	SOCFloor         int     `yaml:"soc_floor"`           // never drain battery below this % (e.g. 5)
+	EODSOCTarget     int     `yaml:"eod_soc_target"`      // target SOC% to reach by sunset (e.g. 90)
+	EODTime          string  `yaml:"eod_time"`            // soft-stop check starts at this time (e.g. "16:00")
+	NoCarRetryMin    int     `yaml:"no_car_retry_min"`    // minutes before retrying after no-car detection
+	PVThresholdAW    float64 `yaml:"pv_threshold_a_w"`    // min PV production to start WallboxA (W)
+	PVThresholdBW    float64 `yaml:"pv_threshold_b_w"`    // min PV production to start WallboxB (W)
+	GridDeltaThreshW float64 `yaml:"grid_delta_thresh_w"` // min grid power shift after WallboxB activation = car detected (W)
+}
+
+func (c *CarChargingConfig) EODTimeParsed(ref time.Time) time.Time {
+	var h, m int
+	fmt.Sscanf(c.EODTime, "%d:%d", &h, &m)
+	return time.Date(ref.Year(), ref.Month(), ref.Day(), h, m, 0, 0, ref.Location())
 }
 
 // CarProfile holds the display name and battery capacity of a known vehicle.
@@ -122,9 +147,11 @@ type StrategicConfig struct {
 	ForecastMidKWh  float64 `yaml:"forecast_mid_kwh"`
 	WWBoostHighC    float64 `yaml:"ww_boost_high_c"`
 	WWBoostMidC     float64 `yaml:"ww_boost_mid_c"`
-	WWBaseC         float64 `yaml:"ww_base_c"`       // normal WW setpoint (°C)
-	WWWindowStart   string  `yaml:"ww_window_start"` // e.g. "12:30"
-	WWWindowEnd     string  `yaml:"ww_window_end"`   // e.g. "18:00"
+	WWBaseC         float64 `yaml:"ww_base_c"`         // normal WW setpoint (°C)
+	WWMaxSetpointC  float64 `yaml:"ww_max_setpoint_c"` // absolute maximum WW setpoint (°C), e.g. 60
+	WWHysteresisC   float64 `yaml:"ww_hysteresis_c"`   // Viessmann switchOn = setpoint - hysteresis (°C), e.g. 5
+	WWWindowStart   string  `yaml:"ww_window_start"`   // e.g. "12:30"
+	WWWindowEnd     string  `yaml:"ww_window_end"`     // e.g. "18:00"
 	ScheduleOn      string  `yaml:"schedule_on"`
 	ScheduleOff     string  `yaml:"schedule_off"`
 }