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/identity/tests/Feature/ManageAppSettingsTest.php

@@ -0,0 +1,71 @@
+<?php
+
+use App\Models\User;
+use Livewire\Livewire;
+use Modules\Identity\Database\Seeders\RolePermissionSeeder;
+use Modules\Identity\Filament\Pages\ManageAppSettings;
+use Modules\Shared\Support\EnvFileWriter;
+
+beforeEach(function () {
+    $this->seed(RolePermissionSeeder::class);
+
+    // Never let a test write to the real project .env — bind the writer to
+    // a throwaway temp file instead.
+    $this->envPath = sys_get_temp_dir().'/manage-app-settings-test-'.uniqid().'.env';
+    file_put_contents($this->envPath, "APP_NAME=Laravel\n");
+    app()->instance(EnvFileWriter::class, new EnvFileWriter($this->envPath));
+});
+
+afterEach(function () {
+    @unlink($this->envPath);
+});
+
+test('an admin without manage_settings is forbidden from the app settings page', function () {
+    $support = User::factory()->create();
+    $support->assignRole('support');
+
+    $this->actingAs($support)->get('/admin/manage-app-settings')->assertForbidden();
+});
+
+test('a super_admin can view and save app settings, writing them to .env', function () {
+    $superAdmin = User::factory()->create();
+    $superAdmin->assignRole('super_admin');
+    $this->actingAs($superAdmin);
+
+    Livewire::test(ManageAppSettings::class)
+        ->assertOk()
+        ->fillForm([
+            'site_name' => 'EV Booking Co',
+            'support_email' => 'help@evbooking.test',
+            'support_phone' => '+95912345678',
+            'timezone' => 'Asia/Yangon',
+            'currency' => 'MMK',
+            'back_seat_enabled' => false,
+            'whole_vehicle_enabled' => true,
+            'front_seat_max_per_booking' => 2,
+        ])
+        ->call('save')
+        ->assertHasNoFormErrors();
+
+    $contents = file_get_contents($this->envPath);
+
+    expect($contents)
+        ->toContain('APP_NAME="EV Booking Co"')
+        ->toContain('SUPPORT_EMAIL=help@evbooking.test')
+        ->toContain('APP_TIMEZONE=Asia/Yangon')
+        ->toContain('APP_CURRENCY=MMK')
+        ->toContain('BOOKING_BACK_SEAT_ENABLED=false')
+        ->toContain('BOOKING_WHOLE_VEHICLE_ENABLED=true')
+        ->toContain('BOOKING_FRONT_SEAT_MAX_PER_BOOKING=2');
+});
+
+test('front seat max per booking must be at least 1', function () {
+    $superAdmin = User::factory()->create();
+    $superAdmin->assignRole('super_admin');
+    $this->actingAs($superAdmin);
+
+    Livewire::test(ManageAppSettings::class)
+        ->fillForm(['front_seat_max_per_booking' => 0])
+        ->call('save')
+        ->assertHasFormErrors(['front_seat_max_per_booking']);
+});