feat(sms): implement SMS messaging and metered billing

Implement a complete SMS messaging system including:
- Integration with SMS Manager.cz API for sending messages.
- Metered billing via Stripe using monthly aggregate invoice items.
- Backend services for managing SMS settings, usage logging, and monthly reporting.
- Database migrations for tenant settings, usage logs, and monthly reports.
- Frontend dashboard components for SMS configuration, usage tracking, and history.
- Support for customer phone numbers in the booking flow.

Includes new migrations, backend services, and frontend UI components.

apps/frontend/src/routes/public-booking-route.tsx

@@ -15,6 +15,7 @@ export function PublicBookingRoute() {
   const [submittingSlot, setSubmittingSlot] = createSignal<string | null>(null);
   const [customerName, setCustomerName] = createSignal("");
   const [customerEmail, setCustomerEmail] = createSignal("");
+  const [customerPhone, setCustomerPhone] = createSignal("");
   const [notes, setNotes] = createSignal("");
   const [highlightContact, setHighlightContact] = createSignal(false);
   let contactFormRef: HTMLDivElement | undefined;
@@ -59,6 +60,7 @@ export function PublicBookingRoute() {
         locationId: slot.locationId ?? undefined,
         customerName: customerName().trim(),
         customerEmail: customerEmail().trim(),
+        customerPhone: customerPhone().trim() || undefined,
         notes: notes().trim(),
         startsAt: slot.startsAt,
         endsAt: slot.endsAt,
@@ -132,6 +134,13 @@ export function PublicBookingRoute() {
                 type="email"
                 value={customerEmail()}
               />
+              <Input
+                autocomplete="tel"
+                label={i18n.t("booking.customer.phone")}
+                onInput={(event) => setCustomerPhone(event.currentTarget.value)}
+                type="tel"
+                value={customerPhone()}
+              />
               <Textarea
                 label={i18n.t("booking.customer.notes")}
                 onInput={(event) => setNotes(event.currentTarget.value)}