feat: data surfacing — intake labels, service metrics, honest capacity

- booking views gain intakeLabels (declared key→label join); dashboard
  modal + manage view render real question labels with slug fallback
- GET /v1/metrics/services aggregates bookings/completed/cancelled/
  revenue per service + classBookings; service-report.csv delegates to
  the same ServiceMetrics aggregation and gains a completed column
- services page gains a Service performance card (per-service stat grid,
  locale CZK revenue, class-bookings footer); demo rows match the
  fabricated service list
- staff capacity utilization subtracts blocked days — tenant-wide and
  staff-scoped blocks remove that day's rule minutes via blockedAt
- tests: blocked-day capacity (tenant + staff scope), service aggregation

Authored By: TDvorak <[email protected]>

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

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

apps/backend/internal/export/service_test.go

@@ -237,7 +237,7 @@ func TestWriteServiceReportCSV(t *testing.T) {
 		t.Fatalf("expected header + service row + class row, got %d rows", len(records))
 	}
 	svcRow := records[1]
-	if svcRow[0] != "Signature treatment" || svcRow[1] != "2" || svcRow[2] != "1" || svcRow[3] != "120000" {
+	if svcRow[0] != "Signature treatment" || svcRow[1] != "2" || svcRow[2] != "0" || svcRow[3] != "1" || svcRow[4] != "120000" {
 		t.Fatalf("unexpected service row: %v", svcRow)
 	}
 	classRow := records[2]