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/shared/intake.go

@@ -24,6 +24,20 @@ func ParseIntakeFields(raw string) []domain.IntakeField {
 	return fields
 }
 
+// IntakeLabels maps a service's declared intake field keys to their display
+// labels, so booking views can render questions rather than slugs.
+func IntakeLabels(raw string) map[string]string {
+	fields := ParseIntakeFields(raw)
+	if len(fields) == 0 {
+		return nil
+	}
+	labels := make(map[string]string, len(fields))
+	for _, field := range fields {
+		labels[field.Key] = field.Label
+	}
+	return labels
+}
+
 // NormalizeIntakeFields validates a service's declared intake fields and
 // returns the canonical JSON string for storage. Keys are slugified from the
 // provided key or the label, must be unique, and fields are capped at 8.