Add status page enhancements and engine improvements

Status page:
- Per-phase grid power (L1/L2/L3) with export/import direction
- Shelly PM live power badge on active wallbox rows
- Compressor power shown below consumer list
- SyncDeviceStates() method on Store for PM power readback

Engine:
- Fix wallbox mutex: re-read Active state after P3 so same-cycle
  WallboxA activation correctly blocks WallboxB in P4
- Fix RecoverState: set ActivatedAt to zero so recovered consumers
  are immediately eligible for shutdown decisions
- Add 3 new unit tests: mutual exclusion, car-not-charging,
  compressor-idle early release

Makefile:
- make install no longer overwrites /etc/ems/ems-config.yaml if it
  already exists (prevents password loss on updates)

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

Makefile

@@ -17,9 +17,14 @@ run: build
 
 install: build
 	install -Dm755 $(BINARY) /usr/local/bin/$(BINARY)
-	install -Dm644 $(CONFIG) /etc/ems/ems-config.yaml
 	install -Dm644 systemd/ems.service /etc/systemd/system/ems.service
 	systemctl daemon-reload
+	@if [ ! -f /etc/ems/ems-config.yaml ]; then \
+		install -Dm644 $(CONFIG) /etc/ems/ems-config.yaml; \
+		echo "Config installed to /etc/ems/ems-config.yaml (first time)"; \
+	else \
+		echo "Config already exists at /etc/ems/ems-config.yaml — not overwritten"; \
+	fi
 	@echo "Run: systemctl enable --now ems"
 
 lint:

internal/status/status.go

@@ -36,6 +36,7 @@ type consumerRecord struct {
 	reason         string
 	manualOverride bool
 	overrideUntil  time.Time
+	livePowerW     float64 // from Shelly PM; 0 for non-PM devices
 }
 
 // Store holds the latest EMS snapshot and is safe for concurrent use.
@@ -118,6 +119,14 @@ type consumerView struct {
 	CanOverride    bool // true for Shelly consumers (hardware read-back available)
 	ManualOverride bool
 	OverrideUntil  time.Time
+	LivePowerW     float64 // from Shelly PM; 0 for non-PM devices
+}
+
+type phaseView struct {
+	Label      string
+	PowerW     float64
+	IsExport   bool
+	AbsPowerW  float64
 }
 
 type forecastView struct {
@@ -128,17 +137,20 @@ type forecastView struct {
 }
 
 type pageData struct {
-	LastUpdate    time.Time
+	LastUpdate       time.Time
-	ErrMsg        string
+	ErrMsg           string
-	DryRun        bool
+	DryRun           bool
-	BatterySOC    float64
+	BatterySOC       float64
-	GridPowerW    float64
+	GridPowerW       float64
-	PVProductionW float64
+	PVProductionW    float64
-	AmbientTempC  float64
+	AmbientTempC     float64
-	IsExporting   bool
+	CompressorPowerW float64
-	AbsGridW      float64
+	IsExporting      bool
-	Forecast      forecastView
+	AbsGridW         float64
-	Consumers     []consumerView
+	HasPhaseData     bool
+	Phases           []phaseView
+	Forecast         forecastView
+	Consumers        []consumerView
 }
 
 // SyncConsumerStates updates active flags for all consumers directly from the
@@ -154,6 +166,18 @@ func (s *Store) SyncConsumerStates(states map[engine.Consumer]bool) {
 	}
 }
 
+// SyncDeviceStates stores live power readings from Shelly PM devices.
+// Called each cycle after ReadAllStates.
+func (s *Store) SyncDeviceStates(states map[engine.Consumer]engine.DeviceStatus) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	for c, status := range states {
+		if rec, ok := s.consumers[c]; ok {
+			rec.livePowerW = status.PowerW
+		}
+	}
+}
+
 // Handler returns an HTTP handler that renders the status page.
 func (s *Store) Handler() http.HandlerFunc {
 	tmpl := template.Must(template.New("status").Funcs(template.FuncMap{
@@ -195,16 +219,32 @@ func (s *Store) Handler() http.HandlerFunc {
 		}
 
 		s.mu.RLock()
+		l1, l2, l3 := s.state.PhaseL1PowerW, s.state.PhaseL2PowerW, s.state.PhaseL3PowerW
+		hasPhase := l1 != 0 || l2 != 0 || l3 != 0
 		data := pageData{
-			LastUpdate:    s.lastUpdate,
+			LastUpdate:       s.lastUpdate,
-			ErrMsg:        s.errMsg,
+			ErrMsg:           s.errMsg,
-			DryRun:        s.dryRun,
+			DryRun:           s.dryRun,
-			BatterySOC:    s.state.BatterySOC,
+			BatterySOC:       s.state.BatterySOC,
-			GridPowerW:    s.state.GridPowerW,
+			GridPowerW:       s.state.GridPowerW,
-			PVProductionW: s.state.PVProductionW,
+			PVProductionW:    s.state.PVProductionW,
-			AmbientTempC:  s.state.AmbientTempC,
+			AmbientTempC:     s.state.AmbientTempC,
-			IsExporting:   s.state.GridPowerW < 0,
+			CompressorPowerW: s.state.CompressorPowerW,
-			AbsGridW:      abs(s.state.GridPowerW),
+			IsExporting:      s.state.GridPowerW < 0,
+			AbsGridW:         abs(s.state.GridPowerW),
+			HasPhaseData:     hasPhase,
+		}
+		if hasPhase {
+			for _, ph := range []struct{ label string; w float64 }{
+				{"L1", l1}, {"L2", l2}, {"L3", l3},
+			} {
+				data.Phases = append(data.Phases, phaseView{
+					Label:     ph.label,
+					PowerW:    ph.w,
+					IsExport:  ph.w < 0,
+					AbsPowerW: abs(ph.w),
+				})
+			}
 		}
 		if s.fcResult != nil {
 			data.Forecast = forecastView{
@@ -227,6 +267,7 @@ func (s *Store) Handler() http.HandlerFunc {
 				CanOverride:    c != engine.ConsumerWW,
 				ManualOverride: rec.manualOverride,
 				OverrideUntil:  rec.overrideUntil,
+				LivePowerW:     rec.livePowerW,
 			}
 			if c == engine.ConsumerWW && !s.wwConfigured {
 				cv.Unconfigured = true
@@ -352,6 +393,41 @@ h1 { font-size: 1.4rem; font-weight: 700; color: #14532d; }
 /* Grid card direction arrow */
 .arrow { font-size: 1.1rem; margin-right: 0.1rem; }
 
+/* Phase grid */
+.phase-grid {
+  display: grid;
+  grid-template-columns: repeat(3, 1fr);
+  gap: 0.5rem;
+  margin-top: 0.75rem;
+}
+.phase-item {
+  text-align: center;
+}
+.phase-label {
+  font-size: 0.65rem;
+  text-transform: uppercase;
+  letter-spacing: 0.05em;
+  color: #9ca3af;
+}
+.phase-value {
+  font-size: 0.9rem;
+  font-weight: 700;
+  margin-top: 0.1rem;
+}
+
+/* Live power badge on consumers */
+.power-badge {
+  font-size: 0.72rem;
+  font-weight: 600;
+  background: #f0fdf4;
+  color: #15803d;
+  border: 1px solid #bbf7d0;
+  border-radius: 6px;
+  padding: 0.15rem 0.45rem;
+  flex-shrink: 0;
+  margin-right: 0.25rem;
+}
+
 /* Consumer list */
 .section-title {
   font-size: 0.7rem;
@@ -476,6 +552,23 @@ h1 { font-size: 1.4rem; font-weight: 700; color: #14532d; }
     <div class="card-value">{{printf "%.1f" .AmbientTempC}}<span style="font-size:1rem;font-weight:400"> °C</span></div>
   </div>
 
+  <!-- Phase power (full width, only if data available) -->
+  {{if .HasPhaseData}}
+  <div class="card full">
+    <div class="card-label">Phasen (Netz)</div>
+    <div class="phase-grid">
+      {{range .Phases}}
+      <div class="phase-item">
+        <div class="phase-label">{{.Label}}</div>
+        <div class="phase-value" style="color:{{if .IsExport}}#16a34a{{else}}#dc2626{{end}}">
+          {{if .IsExport}}↑{{else}}↓{{end}}{{formatW .AbsPowerW}}
+        </div>
+      </div>
+      {{end}}
+    </div>
+  </div>
+  {{end}}
+
   <!-- Forecast (full width) -->
   {{if .Forecast.Available}}
   <div class="card full">
@@ -512,6 +605,9 @@ h1 { font-size: 1.4rem; font-weight: 700; color: #14532d; }
       {{end}}
     </div>
   </div>
+  {{if and .Active .LivePowerW}}
+  <span class="power-badge">{{formatW .LivePowerW}}</span>
+  {{end}}
   {{if .CanOverride}}
   <form method="post" action="/override">
     <input type="hidden" name="consumer" value="{{.ConsumerKey}}">
@@ -527,5 +623,12 @@ h1 { font-size: 1.4rem; font-weight: 700; color: #14532d; }
 </div>
 {{end}}
 
+<!-- Compressor status (shown when SG-Ready context is relevant) -->
+{{if .CompressorPowerW}}
+<div style="margin-top:0.5rem;font-size:0.75rem;color:#9ca3af;text-align:right">
+  Kompressor: {{formatW .CompressorPowerW}}
+</div>
+{{end}}
+
 </body>
 </html>`

main.go

@@ -184,6 +184,7 @@ func runCycle(
 		logger.Warn("all Shelly devices unreachable, skipping override detection", "error", err)
 	} else {
 		eng.SyncHardwareState(shellyStates, now, cfg.EMS.OverrideTimeoutParsed())
+		store.SyncDeviceStates(shellyStates)
 	}
 
 	// Update metrics with current state