Added XML documentation comments to the `JobScheduler` class and its methods.
Added a new method `GetJobStatus` in the `JobScheduler` class for job status retrieval.
Added a new `CollectionHandle` struct for collection management.
Added a new test class `TestUnsafeSparseSet` with unit tests for `UnsafeSparseSet`.
Changed the `WorkerThread` class to improve job retrieval logic with a new `FindJob` method.
Changed the `DynamicArena` class by removing commented-out code to streamline memory management.
Removed commented-out code in the `WorkerThread` class for improved readability.
Removed the `ArenaAllocator` struct from `AllocationManager` to clean up unused code.
Removed the `ParallelWriter` struct from `UnsafeSparseSet`, indicating a shift in handling sparse sets.