feat: implement soft deletes, mailbox reclaims, cooldowns, and auto-cleanup

tests/Feature/MailboxLivewireTest.php

@@ -80,9 +80,6 @@ test('deleting mailbox performs soft delete and clears session', function () {
     Livewire::test(Mailbox::class)
         ->call('deleteMailbox', $mailbox->id);
 
-    // Note: My current implementation of deleteMailbox doesn't use SoftDeletes on the model yet
-    // because I didn't add the trait to the Mailbox model in my implementation.
-    // Let me check if I should add SoftDeletes to Mailbox model.
-    $this->assertDatabaseMissing('mailboxes', ['id' => $mailbox->id]);
+    $this->assertSoftDeleted('mailboxes', ['id' => $mailbox->id]);
     expect(session('current_mailbox_id'))->toBeNull();
 });