Add Booking module: model, create/read/cancel API, Filament resource (T4.1-T4.7)

- Booking model with booking_vehicle_options line items (supports mixing
  vehicle options like front_seat + back_seat in one booking), price
  snapshot, status machine, and driver/car assignment fields
- BookingService: front-seat max, disabled-option toggles, duplicate-option
  and whole-vehicle-exclusivity guards
- CreateBookingAction, CancelBookingAction, AssignDriverAction
- BookingRefGenerator: sequential EVB-AAAAA1-style refs via row lock
- POST/GET/cancel booking API endpoints (Sanctum, ownership + admin policy)
- BookingPlugin + Filament BookingResource: list, detail view, Cancel and
  Assign Driver actions (shared between table and detail page)
- domain.md updated for multi-vehicle-option bookings (§2) and driver/
  vehicle assignment (§5a)

app-modules/booking/src/Enums/BookingChannel.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace Modules\Booking\Enums;
+
+/**
+ * Which external actor created the booking (domain.md §8).
+ */
+enum BookingChannel: string
+{
+    case MiniApp = 'mini_app';
+    case Android = 'android';
+    case Ios = 'ios';
+    case Web = 'web';
+    case Agent = 'agent';
+    case Admin = 'admin';
+}