Add configurable override duration and hard-stop thresholds

Override duration (web UI):
- Dropdown on Ein button: 30min / 1h / 2h / 4h
- Engine notified immediately via ApplyOverride() — no waiting for
  next SyncHardwareState cycle
- Aus button always uses 1h lockout (keeps consumer off for 1h)

Hard-stop thresholds that cancel active overrides:
- SOC emergency brake: now also clears ManualOverride flag so EMS
  resumes full control after the safety shutdown
- override_max_import_w (default 800W): if grid import exceeds this
  while an override is active, override is cancelled immediately
  (no hysteresis delay — protection is instant)

Config: ems.override_max_import_w (0 = disabled)

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

main.go

@@ -104,7 +104,7 @@ func main() {
 		w.WriteHeader(http.StatusOK)
 		w.Write([]byte("ok"))
 	})
-	mux.HandleFunc("/override", overrideHandler(act, logger))
+	mux.HandleFunc("/override", overrideHandler(act, eng, logger))
 	mux.HandleFunc("/", statusStore.Handler())
 
 	srv := &http.Server{
@@ -269,10 +269,9 @@ func shouldRecover(stateFile string, timeout time.Duration, logger *slog.Logger)
 }
 
 // overrideHandler handles manual on/off requests from the status page.
-// For Shelly consumers, it switches the hardware directly; the existing
-// SyncHardwareState mechanism detects the change next cycle and applies
-// the override lockout automatically.
-func overrideHandler(act *actuator.Actuator, logger *slog.Logger) http.HandlerFunc {
+// Switches the hardware immediately and informs the engine directly so
+// the override lockout is applied without waiting for the next cycle.
+func overrideHandler(act *actuator.Actuator, eng *engine.Engine, logger *slog.Logger) http.HandlerFunc {
 	consumerByKey := map[string]engine.Consumer{
 		"sg_ready":  engine.ConsumerSGReady,
 		"wallbox_a": engine.ConsumerWallboxA,
@@ -287,6 +286,7 @@ func overrideHandler(act *actuator.Actuator, logger *slog.Logger) http.HandlerFu
 
 		consumerKey := r.FormValue("consumer")
 		stateVal := r.FormValue("state")
+		durationStr := r.FormValue("duration")
 
 		consumer, ok := consumerByKey[consumerKey]
 		if !ok {
@@ -294,6 +294,11 @@ func overrideHandler(act *actuator.Actuator, logger *slog.Logger) http.HandlerFu
 			return
 		}
 
+		duration, err := time.ParseDuration(durationStr)
+		if err != nil || duration <= 0 {
+			duration = time.Hour // safe default
+		}
+
 		turnOn := stateVal == "on"
 
 		ctx, cancel := context.WithTimeout(r.Context(), 5*time.Second)
@@ -302,7 +307,7 @@ func overrideHandler(act *actuator.Actuator, logger *slog.Logger) http.HandlerFu
 		action := engine.Action{
 			Consumer: consumer,
 			TurnOn:   turnOn,
-			Reason:   "manual override via web UI",
+			Reason:   fmt.Sprintf("manual override via web UI (%s)", duration),
 		}
 		if err := act.Execute(ctx, []engine.Action{action}); err != nil {
 			logger.Error("web UI override failed", "consumer", consumerKey, "state", stateVal, "error", err)
@@ -310,7 +315,14 @@ func overrideHandler(act *actuator.Actuator, logger *slog.Logger) http.HandlerFu
 			return
 		}
 
-		logger.Info("web UI override executed", "consumer", consumerKey, "state", stateVal)
+		// Inform engine immediately so override lockout is active before next cycle
+		eng.ApplyOverride(consumer, turnOn, duration)
+
+		logger.Info("web UI override executed",
+			"consumer", consumerKey,
+			"state", stateVal,
+			"duration", duration,
+		)
 		http.Redirect(w, r, "/", http.StatusSeeOther)
 	}
 }