feat(dashboard): real business metrics with week-over-week trends

Dashboard KPIs were three flat counters with no trend data — the cards
rendered a neutral dash where the design intends movement indicators.
Summary now queries three trailing windows and emits four KPIs with
real deltas: bookings this week, completed (new CompletedCount metric
in both repositories), cancellations, and utilization in percentage
points. KPI labels localize in the frontend via a code-to-key map so
Czech operators no longer see English labels on live data.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

apps/backend/internal/bookings/service.go

@@ -569,6 +569,14 @@ func (s *Service) DashboardSummary(ctx context.Context, principal domain.Princip
 	if err != nil {
 		return domain.DashboardSummary{}, err
 	}
+	previousMetrics, err := s.repo.GetDashboardMetrics(ctx, membership.Tenant.ID, now.AddDate(0, 0, -7), now)
+	if err != nil {
+		return domain.DashboardSummary{}, err
+	}
+	priorMetrics, err := s.repo.GetDashboardMetrics(ctx, membership.Tenant.ID, now.AddDate(0, 0, -14), now.AddDate(0, 0, -7))
+	if err != nil {
+		return domain.DashboardSummary{}, err
+	}
 	upcomingRecords, err := s.repo.ListBookingsByTenantBetween(ctx, membership.Tenant.ID, now, weekEnd)
 	if err != nil {
 		return domain.DashboardSummary{}, err
@@ -614,9 +622,10 @@ func (s *Service) DashboardSummary(ctx context.Context, principal domain.Princip
 		PublicBookingURL: "/book/" + membership.Tenant.Slug,
 		SetupCompletion:  setupCompletion(brandName, len(locationNames), len(serviceNames), len(staffNames), scheduleCount),
 		KPIs: []domain.DashboardKPI{
-			{Code: "bookings_this_week", Label: "Bookings this week", Value: fmt.Sprintf("%d", metrics.BookingsCount)},
-			{Code: "cancellations", Label: "Cancellations", Value: fmt.Sprintf("%d", metrics.CancellationsCount)},
-			{Code: "utilization", Label: "Utilization", Value: fmt.Sprintf("%d%%", metrics.UtilizationPercent)},
+			dashboardKPI("bookings_this_week", "Bookings this week", metrics.BookingsCount, previousMetrics.BookingsCount, ""),
+			dashboardKPI("completed", "Completed", previousMetrics.CompletedCount, priorMetrics.CompletedCount, ""),
+			dashboardKPI("cancellations", "Cancellations", metrics.CancellationsCount, previousMetrics.CancellationsCount, ""),
+			dashboardKPI("utilization", "Utilization", metrics.UtilizationPercent, previousMetrics.UtilizationPercent, "%"),
 		},
 		UpcomingBookings: upcoming,
 		AllBookings:      allBookings,
@@ -909,3 +918,20 @@ func reminderSchedule(startsAt time.Time) (time.Time, bool) {
 		return time.Time{}, false
 	}
 }
+
+func dashboardKPI(code, label string, current int, previous int, suffix string) domain.DashboardKPI {
+	delta := current - previous
+	change := "0"
+	trend := "neutral"
+	if delta > 0 {
+		change = fmt.Sprintf("+%d", delta)
+		trend = "up"
+	} else if delta < 0 {
+		change = fmt.Sprintf("%d", delta)
+		trend = "down"
+	}
+	if suffix != "" && change != "0" {
+		change += suffix
+	}
+	return domain.DashboardKPI{Code: code, Label: label, Value: fmt.Sprintf("%d%s", current, suffix), Change: change, Trend: trend}
+}

apps/backend/internal/bookings/service_test.go

@@ -450,3 +450,71 @@ func TestCustomerCancelPromotesWaitlist(t *testing.T) {
 		t.Fatalf("expected waiter promoted to confirmed, got %q", booking.Status)
 	}
 }
+
+func TestDashboardSummaryComputesKPIsWithTrends(t *testing.T) {
+	repo := db.NewMemoryRepository()
+	service := NewService(repo, nil, "http://localhost:3000")
+	ctx := context.Background()
+
+	membership, err := repo.GetTenantMembershipBySubject(ctx, "demo-owner")
+	if err != nil {
+		t.Fatalf("membership: %v", err)
+	}
+	tenantID := membership.Tenant.ID
+
+	now := time.Now().UTC()
+	seed := func(offsetDays int, hours int, status string) {
+		t.Helper()
+		starts := now.AddDate(0, 0, offsetDays).Add(time.Duration(hours) * time.Hour)
+		_, err := repo.CreateBooking(ctx, db.CreateBookingParams{
+			TenantID:    tenantID,
+			BookingMode: "appointment",
+			StartsAt:    starts,
+			EndsAt:      starts.Add(time.Hour),
+			Status:      status,
+			Reference:   "BK-T",
+		})
+		if err != nil {
+			t.Fatalf("seed booking: %v", err)
+		}
+	}
+
+	// Next 7 days: 3 bookings, one cancelled.
+	seed(1, 0, "confirmed")
+	seed(2, 0, "confirmed")
+	seed(3, 0, "cancelled")
+	// Last 7 days: 1 confirmed booking that already ended.
+	seed(-2, 0, "confirmed")
+	// 7-14 days ago: 2 completed bookings.
+	seed(-8, 0, "confirmed")
+	seed(-9, 0, "confirmed")
+
+	summary, err := service.DashboardSummary(ctx, domain.Principal{Subject: "demo-owner", Role: "owner"})
+	if err != nil {
+		t.Fatalf("dashboard summary: %v", err)
+	}
+	if len(summary.KPIs) != 4 {
+		t.Fatalf("expected 4 kpis, got %d", len(summary.KPIs))
+	}
+	byCode := map[string]domain.DashboardKPI{}
+	for _, kpi := range summary.KPIs {
+		byCode[kpi.Code] = kpi
+	}
+
+	bookings := byCode["bookings_this_week"]
+	if bookings.Value != "3" || bookings.Change != "+2" || bookings.Trend != "up" {
+		t.Fatalf("bookings kpi = %+v", bookings)
+	}
+	completed := byCode["completed"]
+	if completed.Value != "1" || completed.Change != "-1" || completed.Trend != "down" {
+		t.Fatalf("completed kpi = %+v", completed)
+	}
+	cancellations := byCode["cancellations"]
+	if cancellations.Value != "1" || cancellations.Change != "+1" || cancellations.Trend != "up" {
+		t.Fatalf("cancellations kpi = %+v", cancellations)
+	}
+	utilization := byCode["utilization"]
+	if utilization.Value != "66%" || utilization.Trend != "down" {
+		t.Fatalf("utilization kpi = %+v", utilization)
+	}
+}

apps/backend/internal/db/bookings.go

@@ -179,13 +179,15 @@ func (r *PGRepository) GetDashboardMetrics(ctx context.Context, tenantID string,
 					/ NULLIF(COUNT(*) FILTER (WHERE starts_at >= $2 AND starts_at < $3), 0)
 				),
 				0
-			)::integer AS utilization_percent
+			)::integer AS utilization_percent,
+			COUNT(*) FILTER (WHERE starts_at >= $2 AND starts_at < $3 AND status = 'confirmed' AND ends_at < now()) AS completed_count
 		FROM bookings
 		WHERE tenant_id = $1
 	`, tenantID, startsAt, endsAt).Scan(
 		&metrics.BookingsCount,
 		&metrics.CancellationsCount,
 		&metrics.UtilizationPercent,
+		&metrics.CompletedCount,
 	)
 	return metrics, err
 }

apps/backend/internal/db/repository.go

@@ -394,6 +394,7 @@ type DashboardMetrics struct {
 	BookingsCount      int
 	CancellationsCount int
 	UtilizationPercent int
+	CompletedCount     int
 }
 
 type ReminderJobParams struct {
@@ -1452,6 +1453,9 @@ func (r *MemoryRepository) GetDashboardMetrics(_ context.Context, tenantID strin
 		}
 		if booking.Status == "confirmed" {
 			metrics.UtilizationPercent++
+			if booking.EndsAt.Before(time.Now().UTC()) {
+				metrics.CompletedCount++
+			}
 		}
 	}
 	if metrics.BookingsCount == 0 {

apps/backend/internal/domain/models.go

@@ -10,9 +10,11 @@ type Principal struct {
 }
 
 type DashboardKPI struct {
-	Code  string `json:"code"`
-	Label string `json:"label"`
-	Value string `json:"value"`
+	Code   string `json:"code"`
+	Label  string `json:"label"`
+	Value  string `json:"value"`
+	Change string `json:"change,omitempty"`
+	Trend  string `json:"trend,omitempty"`
 }
 
 type UpcomingBooking struct {