Memory Runtime
src/memory/ stays thin by design: allocator.zig re-exports the std.mem.Allocator interface with small helpers; arena.zig wraps std.heap.ArenaAllocator (init/deinit/allocator/reset/queryCapacity); refcount.zig is an atomic RefCount for future shared structures; ownership.zig documents the borrow/own vocabulary (OwnerToken). The deliberate non-goal is a custom allocator framework — the standard facilities plus pooled tree storage already give the hot paths zero per-node allocation.