fix(reminders): re-arm reminder jobs on waitlist promotion

A booking promoted off the waitlist after its reminder had already
dispatched-as-skipped went unreminded. Promotion now clears pending
jobs and re-arms via the shared armReminderJobs helper — extracted
from booking creation so both paths arm email plus opt-in SMS.

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

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

apps/backend/internal/bookings/lifecycle.go

@@ -57,8 +57,42 @@ func PromoteWaitlist(ctx context.Context, repo db.Repository, tenantID, sessionI
 			return promoted, err
 		}
 		_ = repo.ResolveWaitlistEntry(ctx, tenantID, sessionID, booking.CustomerEmail)
+		// A booking promoted after its reminder already dispatched-as-skipped
+		// would otherwise go unreminded; re-arm whatever the horizon allows.
+		_ = repo.DeletePendingReminderJobsForBooking(ctx, booking.ID)
+		_ = armReminderJobs(ctx, repo, tenantID, booking.ID, booking.StartsAt, booking.CustomerPhone)
 		confirmed++
 		promoted = append(promoted, booking)
 	}
 	return promoted, nil
 }
+
+// armReminderJobs schedules the email reminder — and the SMS reminder when the
+// tenant opted into SMS and a phone number is on file — for a booking whose
+// start still falls inside a reminder horizon. A start too close or too far
+// away simply arms nothing.
+func armReminderJobs(ctx context.Context, repo db.Repository, tenantID, bookingID string, startsAt time.Time, customerPhone string) error {
+	scheduledFor, ok := reminderSchedule(startsAt)
+	if !ok {
+		return nil
+	}
+	if err := repo.CreateReminderJob(ctx, db.ReminderJobParams{
+		TenantID:     tenantID,
+		BookingID:    bookingID,
+		Channel:      "email",
+		ScheduledFor: scheduledFor,
+	}); err != nil {
+		return err
+	}
+	if customerPhone != "" {
+		if smsSettings, err := repo.GetTenantSMSSettings(ctx, tenantID); err == nil && smsSettings.Enabled {
+			_ = repo.CreateReminderJob(ctx, db.ReminderJobParams{
+				TenantID:     tenantID,
+				BookingID:    bookingID,
+				Channel:      "sms",
+				ScheduledFor: scheduledFor,
+			})
+		}
+	}
+	return nil
+}

apps/backend/internal/bookings/service.go

@@ -357,26 +357,8 @@ func (s *Service) Create(ctx context.Context, request domain.CreateBookingReques
 		}
 	}
 
-	if scheduledFor, ok := reminderSchedule(startsAt); ok {
-		if err := s.repo.CreateReminderJob(ctx, db.ReminderJobParams{
-			TenantID:     tenant.ID,
-			BookingID:    created.ID,
-			Channel:      "email",
-			ScheduledFor: scheduledFor,
-		}); err != nil {
-			return domain.CreateBookingResponse{}, err
-		}
-		// SMS reminders are a per-tenant opt-in and need a customer phone.
-		if request.CustomerPhone != "" {
-			if smsSettings, err := s.repo.GetTenantSMSSettings(ctx, tenant.ID); err == nil && smsSettings.Enabled {
-				_ = s.repo.CreateReminderJob(ctx, db.ReminderJobParams{
-					TenantID:     tenant.ID,
-					BookingID:    created.ID,
-					Channel:      "sms",
-					ScheduledFor: scheduledFor,
-				})
-			}
-		}
+	if err := armReminderJobs(ctx, s.repo, tenant.ID, created.ID, startsAt, request.CustomerPhone); err != nil {
+		return domain.CreateBookingResponse{}, err
 	}
 
 	// Send confirmation emails (async - don't fail booking if email fails)

project.md

@@ -119,6 +119,7 @@
 - `[done/partial]` Milestone 18: Public class list polish
   - class sessions on the public booking page are now grouped by day (localized weekday + date headers) with compact timetable-style rows instead of one tall card per session — consistent with the stepped appointment picker above
   - capacity states read honestly: spots-left in success/warning tones, `Obsazeno`/`Full` when empty, and the action switches to `Na čekací listinu`/`Join waitlist` (previously a full session still said "Book now" while silently producing a waitlisted booking)
+  - reminder arming extracted into a shared `armReminderJobs` helper (email + opt-in SMS) used by booking creation and waitlist promotion — a booking promoted after its reminder already dispatched-as-skipped now gets re-armed instead of going unreminded
   - remaining: live staging validation
 
 ## Overview