sefer-alloc 0.2.0

A safe-by-construction, 100% Rust memory toolkit (no C/C++ libraries — no libnuma/mimalloc/jemalloc/snmalloc/tcmalloc): a single-threaded handle store (Region<T>) and a drop-in #[global_allocator] (SeferAlloc) over one verified segment substrate, with #![forbid(unsafe_code)] at the top.