Bump go-cart-actor: scheduling cluster service + booking-hold cart/checkout seam

Deploys cmd/scheduling as a 3-replica actor cluster (shared RWX commerce-data
event logs, gRPC mesh via POD_IP + actor-pool label, edge /api/scheduling
pass-through, fail-closed mcpauth on admin/MCP). cart/checkout get
SCHEDULING_SERVICE_URL so line removal releases holds; backoffice gets
SCHEDULING_URL for the admin proxy. Platform seam: order.Line.Properties
carries booking_* fields through order.created; scheduling.booking_confirmed/
cancelled event types. Compose + prep-dev-data wire the schedules dir.

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Co-Authored-By: Codebuff <noreply@codebuff.com>

event/event.go

@@ -88,6 +88,10 @@ const (
 	// credit notes (invoice.credited), so RefundIssued never fires for them.
 	RefundIssued Type = "refund.issued"
 
+	// Scheduling (go-cart-actor cmd/scheduling). Emitted when timeslots are
+	// confirmed from an order capture or cancelled.
+	SchedulingBookingConfirmed Type = "scheduling.booking_confirmed"
+	SchedulingBookingCancelled Type = "scheduling.booking_cancelled"
 
 	// Analytics (tracking). Replaces the integer enum 0–6 that finder and
 	// slask-tracking use on the `tracking` topic today. Producer: slask-finder