- Add PickRenderableFormat / IsColorAttachmentSupported so 3-channel
Vulkan formats fall back to 4-channel when unsupported.
- Make oakvulkan target and C ABI check conditional on Vulkan_FOUND;
skip liboakvulkan build/dependencies when Vulkan headers/libs are
absent.
- Update Preferences tooltip to reflect Vulkan is an experimental
prototype that may fall back to OpenGL.
- Revise dynamic backend plan doc: phase 3/4/5 described as prototype
frameworks with runtime validation pending, and list recent Vulkan
fixes (init idempotency, descriptor/sampler lifetime, dynamic
viewport/scissor, render pass clear, format probing).
Both OAK_ENABLE_DYNAMIC_RENDER_BACKEND=ON and OFF configurations
build and pass ctest (4/4).
Mike-Solar