Fix T94022: Both options GPU/CPU checked under preferences cause viewport render crash. (ARM/Metal)

This fixes crash T94022 when selecting live viewport render with both GPU & CPU devices selected. It is caused by incorrect `KernelBVHLayout` assignment. Similar to `BVH_LAYOUT_MULTI_OPTIX` for Optix, this patch adds a `BVH_LAYOUT_MULTI_METAL` to correctly redirect to the correct Metal BVH layout type.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D13561

Cycles: Fix OS version warnings

This patch suppresses OS version warnings and hides currently unsupported Metal GPUs when enumerating devices.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D13506

Cycles: Metal host-side code

This patch adds the Metal host-side code:

- Add all core host-side Metal backend files (device_impl, queue, etc)
- Add MetalRT BVH setup files
- Integrate with Cycles device enumeration code
- Revive `path_source_replace_includes` in util/path (required for MSL compilation)

This patch also includes a couple of small kernel-side fixes:

- Add an implementation of `lgammaf` for Metal [Nemes, Gerg? (2010), "New asymptotic expansion for the Gamma function", Archiv der Mathematik](https://users.renyi.hu/~gergonemes/)
- include "work_stealing.h" inside the Metal context class because it accesses state now

Ref T92212

Reviewed By: brecht

Maniphest Tasks: T92212

Differential Revision: https://developer.blender.org/D13423

Cycles: Fix Metal BVH crash caused by missing `WITH_METAL` define

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D13505

Cycles: Fix Metal BVH crash caused by missing `WITH_METAL` define

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D13505

Cycles: Metal host-side code

This patch adds the Metal host-side code:

- Add all core host-side Metal backend files (device_impl, queue, etc)
- Add MetalRT BVH setup files
- Integrate with Cycles device enumeration code
- Revive `path_source_replace_includes` in util/path (required for MSL compilation)

This patch also includes a couple of small kernel-side fixes:

- Add an implementation of `lgammaf` for Metal [Nemes, Gerg? (2010), "New asymptotic expansion for the Gamma function", Archiv der Mathematik](https://users.renyi.hu/~gergonemes/)
- include "work_stealing.h" inside the Metal context class because it accesses state now

Ref T92212

Reviewed By: brecht

Maniphest Tasks: T92212

Differential Revision: https://developer.blender.org/D13423

Cycles: MetalRT support (kernel side)

This patch adds MetalRT support to Cycles kernel code. It is mostly additive in nature or confined to Metal-specific code, however there are a few areas where this interacts with other code:

- MetalRT closely follows the Optix implementation, and in some cases (notably handling of transforms) it makes sense to extend Optix special-casing to MetalRT. For these generalisations we now have `__KERNEL_GPU_RAYTRACING__` instead of `__KERNEL_OPTIX__`.
- MetalRT doesn't support primitive offsetting (as with `primitiveIndexOffset` in Optix), so we define and populate a new kernel texture, `__object_prim_offset`, containing per-object primitive / curve-segment offsets. This is referenced and applied in MetalRT intersection handlers.
- Two new BVH layout enum values have been added: `BVH_LAYOUT_METAL` and `BVH_LAYOUT_MULTI_METAL_EMBREE` for XPU mode). Some host-side enum case handling has been updated where it is trivial to do so.

Ref T92212

Reviewed By: brecht

Maniphest Tasks: T92212

Differential Revision: https://developer.blender.org/D13353

Cycles: Metal readiness: Specify DeviceQueue::enqueue arg types

This patch adds new arg-type parameters to `DeviceQueue::enqueue` and its overrides. This is in preparation for the Metal backend which needs this information for correct argument encoding.

Ref T92212

Reviewed By: brecht

Maniphest Tasks: T92212

Differential Revision: https://developer.blender.org/D13357

Cycles: Fix film convert address space mismatch on Metal

This patch fixes an address space mismatch in the film convert kernels on Metal. The `film_get_pass_pixel_...` functions take a `ccl_private` result pointer, but the film convert kernels pass a `ccl_global` memory pointer. Specialising the pass-fetch functions with templates results in compilation errors on Visual Studio, so instead this patch just adds an intermediate local on Metal.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D13350

Cycles: declare constants at program scope on Metal

MSL requires that constant address space literals be declared at program
scope. This patch moves the `blackbody_table_r/g/b` and `cie_colour_match`
constants into separate files so they can be declared at the appropriate scope.

Ref T92212

Differential Revision: https://developer.blender.org/D13241