fix(memory): ArenaAllocator::Allocate missing explicit power-of-two alignment precondition

[JeanPhilippeKernel]

Summary

ArenaAllocator::Allocate(size_t size, size_t alignment) has no explicit assertion that alignment is a power of two before calling memory_align().

Location

ZEngine/ZEngine/Core/Memory/Allocator.cpp:60 — ArenaAllocator::Allocate

Detail

The power-of-two assertion exists inside Helpers::memory_align() (MemoryOperations.h:172):

ZENGINE_VALIDATE_ASSERT(is_power_of_two(align), "Alignment should be power of two");

And Resize() adds its own explicit assert at Allocator.cpp:112:

ZENGINE_VALIDATE_ASSERT(Helpers::is_power_of_two(alignment), "Alignment should be power of 2")

But Allocate() has no such guard at the call site. Defensive programming should assert the precondition directly in Allocate() before delegating to the helper — consistent with how Resize() handles it.

Fix

Add at the top of Allocate():

ZENGINE_VALIDATE_ASSERT(Helpers::is_power_of_two(alignment), "ArenaAllocator::Allocate: alignment must be a power of two");

Impact

Low — the assertion fires inside memory_align() regardless, so no allocation with a bad alignment succeeds silently. This is a defensive programming / consistency gap, not a silent failure.