Add Access group admin surfaces, booking soft deletes, refund crash fix

Access group (Filament):
- StaffResource: manage users with an admin-tier role, gated by manage_staff
- CustomerResource: read-only view of role-less users, gated by view_customers
- RoleResource: edit permissions per role (fixed role set), gated by manage_roles
- ManageAppSettings: tabbed General/Booking settings page that reads/writes
  real .env keys via new EnvFileWriter (no parallel DB settings table, so
  BookingService/config('booking.*') stay unchanged)
- Moved Access above Catalog in the nav group order
- New permissions: manage_staff, manage_roles, view_customers, manage_settings

Booking soft deletes:
- bookings.deleted_at + SoftDeletes on the Booking model
- BookingPolicy::delete (manage_bookings, cancelled/expired only) and
  ::restore (manage_bookings)
- DeleteBookingTableAction/RestoreBookingTableAction + TrashedFilter on
  BookingsTable, using authorize() so the policy is enforced at call time,
  not just cosmetically hidden

Refund crash fix:
- ProcessRefundAction passed a nullable $payment->booking into
  RefundBookingAction's non-nullable Booking param — a soft-deleted
  booking's payment reaching the refund picker was an uncaught TypeError.
  Excluded such payments from the picker and added a defensive guard.
- Same unguarded $event->payment->booking / $event->refund->payment->booking
  pattern fixed in the MarkBookingPaid/MarkBookingRefunded queued listeners.

289 tests passing.

app-modules/booking/src/Filament/Resources/Bookings/Actions/RestoreBookingTableAction.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace Modules\Booking\Filament\Resources\Bookings\Actions;
+
+use Filament\Actions\RestoreAction;
+
+/**
+ * Pairs with DeleteBookingTableAction — RestoreAction is already visible
+ * only for trashed records out of the box; authorize('restore') layers
+ * BookingPolicy::restore (manage_bookings) on top, enforced at call time
+ * as well as driving visibility (Filament\Actions\Concerns\CanBeAuthorized).
+ */
+class RestoreBookingTableAction
+{
+    public static function make(): RestoreAction
+    {
+        return RestoreAction::make()
+            ->authorize('restore');
+    }
+}