feat(bookings): dashboard cancellation and waitlist promotion

- POST /v1/catalog/bookings/{id}/cancel lets businesses cancel
  tenant-owned bookings; two-step confirm in the detail modal
- Shared PromoteWaitlist helper promotes earliest waitlisted bookings
  when a class seat frees, on both dashboard and customer cancel paths;
  promoted customers get a confirmation email, waitlist ledger marked
  resolved
- waitlisted status surfaced in bookings UI: stats card, filter, warning
  badge, demo seed, CS+EN strings
- BookingRecord gains created_at for fair ordering; GetBookingByID and
  ResolveWaitlistEntry added to the repository surface

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

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

apps/frontend/src/routes/dashboard/dashboard-data.ts

@@ -48,6 +48,7 @@ function createDemoData(i18n: ReturnType<typeof useI18n>) {
     { id: "b6", customerName: customers[0].name, customerEmail: customers[0].email, service: services[1], status: "confirmed", startsAt: fmt(at(3, 10)), endsAt: fmt(at(3, 11)), reference: "BOK-006", location: salonA, staffName: staff1, notes: "" },
     { id: "b8", customerName: customers[2].name, customerEmail: customers[2].email, service: services[3], status: "pending", startsAt: fmt(at(4, 9)), endsAt: fmt(at(4, 10)), reference: "BOK-008", location: salonA, staffName: staff2, notes: "" },
     { id: "b9", customerName: customers[3].name, customerEmail: customers[3].email, service: services[0], status: "confirmed", startsAt: fmt(at(5, 11)), endsAt: fmt(at(5, 12)), reference: "BOK-009", location: salonA, staffName: staff1, notes: "" },
+    { id: "b13", customerName: customers[0].name, customerEmail: customers[0].email, service: cs ? "Jóga pro začátečníky" : "Beginner yoga", status: "waitlisted", startsAt: fmt(at(3, 18)), endsAt: fmt(at(3, 19)), reference: "BOK-013", location: salonA, staffName: "", notes: "" },
   ];
 
   return {