`Material::Initialize()` dereferences a possibly-null buffer

[CanReader]

src/Graphics/Common/Material.cpp:15-20; src/Graphics/Common/ResourceManager.cpp:24;
include/.../SmartPointer.hpp:37

m_materialBuffer->SetSlot(1) at :15-20 is unguarded, but ResourceManager::CreateBuffer returns nullptr
on failure (ResourceManager.cpp:24) and SmartPointer::operator-> does not null-check (SmartPointer.hpp:37).

What marks this as a genuine oversight rather than an accepted invariant: every other use of
m_materialBuffer in the same file is guarded.

Runs on every backend. Severity: crash.

Found by a full audit of the graphics layer. Assessed severity: crash.