- Container: Use hasContainer() instead of is_null(getContainer())
- CallQueuedListener: Add ignore for defensive deserialization check
- Kernel: Fix PHPDoc to include null for optional upload files
- TestResponseAssert: Remove dead is_string() check on Throwable parameter
- ContinueSupervisorCommand/PauseSupervisorCommand: Check === 0 instead of is_null after (int) cast
- MailManager: Fix return type to ?array (config lookup can return null)
- MailMessage: Make priority nullable with default null
- QueueManager: Remove redundant is_null() on string parameter
- RedisQueue: Remove dead if wrapper (retryAfter always int)