feat(reminders): SMS channel for reminder jobs

Tenants paying for the SMS add-on still got email-only reminders —
the channel column existed but nothing armed or dispatched sms jobs.
Booking creation now adds a second job when SMS is enabled and the
customer left a phone; dispatch routes sms jobs through an injected
sender adapter wired to the existing sms.Service, so monthly limits,
usage metering, and Stripe billing apply unchanged. Lifecycle handling
from the previous milestone clears and re-arms both channels together.

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

apps/backend/internal/db/repository.go

@@ -418,6 +418,7 @@ type ReminderJobRecord struct {
 	ScheduledFor  time.Time
 	CustomerName  string
 	CustomerEmail string
+	CustomerPhone string
 	Reference     string
 	StartsAt      time.Time
 	Status        string
@@ -1386,12 +1387,14 @@ func (r *MemoryRepository) CreateReminderJob(_ context.Context, params ReminderJ
 	startsAt := time.Now().UTC()
 	customerName := "Booking Customer"
 	customerEmail := "[email protected]"
+	customerPhone := ""
 	for _, booking := range r.bookings {
 		if booking.ID == params.BookingID {
 			reference = booking.Reference
 			startsAt = booking.StartsAt
 			customerName = booking.CustomerName
 			customerEmail = booking.CustomerEmail
+			customerPhone = booking.CustomerPhone
 			break
 		}
 	}
@@ -1406,6 +1409,7 @@ func (r *MemoryRepository) CreateReminderJob(_ context.Context, params ReminderJ
 		ScheduledFor:  params.ScheduledFor,
 		CustomerName:  customerName,
 		CustomerEmail: customerEmail,
+		CustomerPhone: customerPhone,
 		Reference:     reference,
 		StartsAt:      startsAt,
 		Status:        "pending",
@@ -1420,6 +1424,7 @@ func (r *MemoryRepository) ListDueReminderJobs(_ context.Context, dueBefore time
 			for _, booking := range r.bookings {
 				if booking.ID == job.BookingID {
 					job.BookingStatus = booking.Status
+					job.CustomerPhone = booking.CustomerPhone
 					break
 				}
 			}