feat: series-aware schedule edits + waitlist ledger removal (M32)

PATCH /v1/catalog/class-schedules/:id patches a recurring rule and,
with applyToFuture, retimes materialized future sessions to the new
local start time on their existing dates — moving confirmed and
waitlisted bookings with them and re-arming reminders. Zones-page
schedule rows gain an inline editor (CS/EN).

Also drops the vestigial waitlist_entries table (migration 00020):
positions derive from bookings.created_at, so the ledger was written
but never read.

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

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

apps/backend/internal/db/bookings.go

@@ -127,25 +127,6 @@ func (r *PGRepository) CreateBooking(ctx context.Context, params CreateBookingPa
 	return created, err
 }
 
-func (r *PGRepository) AppendWaitlistEntry(ctx context.Context, params WaitlistEntryParams) error {
-	_, err := r.pool.Exec(ctx, `
-		INSERT INTO waitlist_entries (tenant_id, class_session_id, customer_name, customer_email, position)
-		VALUES ($1,$2,$3,$4,$5)
-	`, params.TenantID, params.ClassSessionID, params.CustomerName, params.CustomerEmail, params.Position)
-	return err
-}
-
-// ResolveWaitlistEntry marks the pending ledger row for a promoted booking.
-// Entries carry no booking_id, so the session + customer email pair is the
-// practical key.
-func (r *PGRepository) ResolveWaitlistEntry(ctx context.Context, tenantID, sessionID, customerEmail string) error {
-	_, err := r.pool.Exec(ctx, `
-		UPDATE waitlist_entries SET status = 'resolved'
-		WHERE tenant_id = $1 AND class_session_id = $2 AND customer_email = $3 AND status = 'pending'
-	`, tenantID, sessionID, customerEmail)
-	return err
-}
-
 func (r *PGRepository) CreateReminderJob(ctx context.Context, params ReminderJobParams) error {
 	_, err := r.pool.Exec(ctx, `
 		INSERT INTO reminder_jobs (tenant_id, booking_id, channel, scheduled_for)