Major overhaul of GPU resource/heap management:
- Replace resource pooling and upload buffer logic with transient heap/page-based suballocation in ResourceManager.
- Add support for suballocation and heap flags/types, with D3D12 helpers.
- Remove ICommandBuffer.UploadBuffer/UploadTexture; add UpdateSubResources and CopyBuffer, move upload logic to RenderingContext.
- Refactor D3D12ResourceAllocator/Database for suballocation, heap flags, and mapping.
- Standardize on Handle<GPUBuffer> usage.
- Update meshlet/mesh utilities for new allocation handles and memory pools.
- Refactor RenderGraph and docs to use "heap" terminology.
- Use cpuFrame/gpuFrame consistently for frame sync.
- Add s2h.hlsl, s2h_3d.hlsl, s2h_scatter.hlsl shader debug libs.
- Miscellaneous fixes, cleanup, and dependency updates.
BREAKING CHANGE: Resource pooling and upload APIs replaced with new heap/page-based suballocation system. Update all buffer/texture creation and upload code to use new ResourceManager and ICommandBuffer methods.
- RenderGraph.Compile/Execute now return Error for better failure detection; error handling is propagated throughout compiler and executor.
- Renamed ScheduleReleaseResource to ReleaseResource for clarity; updated all usages.
- ResourceManager now calls ReleaseResource directly on Mesh, Material, and Shader types.
- Camera exposes Actual/Virtual size properties and Render returns Error.
- RenderingContext now uses IResourceManager for mesh/resource ops.
- Replaced custom BinaryWriter with BufferWriter in RenderGraphHasher.
- Improved variable naming, interface signatures, and code formatting.
- Added Error extension for IsSuccess/IsFailure.
- Minor FMOD/native interop and test code cleanups.
- No breaking API changes except for new Error return values on some methods.
