Добавлены метрики Prometheus и дашборды Grafana (этап 2.5)

Все три Go-сервиса (ingest, device-control, rule-engine) отдают
/metrics в формате Prometheus: счётчики MQTT/RabbitMQ/ClickHouse
операций, гистограммы длительности батч-флашей и диспатча правил,
переходы устройств online/offline. Добавлены сервисы prometheus и
grafana в docker-compose с провижининг конфигом (datasource +
два готовых дашборда: "Ingest & Telemetry" и "Automation & Devices").

services/device-control-service/internal/server/server_test.go

@@ -8,7 +8,10 @@ import (
 	"log/slog"
 	"testing"
 
+	"github.com/prometheus/client_golang/prometheus/testutil"
+
 	devicecontrol "git.cactoz.su/cacto/home_automatization/proto/device_control"
+	"git.cactoz.su/cacto/home_automatization/services/device-control-service/internal/metrics"
 )
 
 type fakeShadow struct {
@@ -122,3 +125,27 @@ func TestDispatch_PublishFailure(t *testing.T) {
 		t.Fatal("expected failure when mqtt publish errors")
 	}
 }
+
+func TestDispatch_RecordsMetrics(t *testing.T) {
+	successCounter := metrics.CommandsTotal.WithLabelValues("turn_on", "success")
+	errorCounter := metrics.CommandsTotal.WithLabelValues("turn_on", "error")
+	before := testutil.ToFloat64(successCounter)
+
+	s := New(&fakeShadow{}, &fakeMQTT{}, discardLogger())
+	if _, err := s.TurnOn(context.Background(), &devicecontrol.TurnOnRequest{DeviceId: "d1"}); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if got := testutil.ToFloat64(successCounter); got != before+1 {
+		t.Fatalf("got turn_on/success counter %v, want %v", got, before+1)
+	}
+
+	beforeErr := testutil.ToFloat64(errorCounter)
+	s2 := New(&fakeShadow{err: errors.New("redis down")}, &fakeMQTT{}, discardLogger())
+	if _, err := s2.TurnOn(context.Background(), &devicecontrol.TurnOnRequest{DeviceId: "d1"}); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if got := testutil.ToFloat64(errorCounter); got != beforeErr+1 {
+		t.Fatalf("got turn_on/error counter %v, want %v", got, beforeErr+1)
+	}
+}