WebAssembly memory64: 32-bit to 64-bit linear memory compatibility boundary
Goal: paginate a guest-language dataset stored in Wasm linear memory using offset-and-length slices when the working set may exceed the 32-bit 4 GiB limit. Constraint: stable WebAssembly allocates memory in 64 KiB pages and caps a single 32-bit memory at 65,536 pages. memory.grow returns the previous size in pages or -1 when growth cannot be satisfied, witho