Introduce VirtualStack allocator, refactor memory management to use virtual memory stacks, and update documentation.
Added VirtualStack as a new stack allocator using virtual memory, replaced Stack with VirtualStack in allocation manager and related APIs, and updated TempJobAllocator to use VirtualArena. Introduced AllocationManagerInitOpts for allocator configuration. Replaced ENABLE_COLLECTION_CHECKS with ENABLE_SAFETY_CHECKS for safety checks. Removed Result.cs and updated project files and examples. Added comprehensive README files for all major packages and improved root documentation.
BREAKING CHANGE: Stack allocator replaced by VirtualStack; TempJobAllocator and AllocationManager initialization signatures changed; Result types removed.
Refactored FreeList allocator to use per-thread caches for improved scalability and performance, with configurable max concurrency and overflow cache. AllocationManager debug layer is now compile-time via ENABLE_DEBUG_LAYER. MemoryUtility methods no longer catch exceptions. Argument validation standardized with ThrowIfNegative. JobScheduler passes maxConcurrencyLevel to allocator. CollectionUtility's GetElementUnsafe returns mutable ref. AssemblyVersion incremented. Added comprehensive FreeList unit tests. Improved robustness and error handling in allocation classes.
BREAKING CHANGE: Debug layer APIs removed; FreeList allocator interface changed for thread cache support.
