Use the same hash factory for a local that reads stored hash state

Replace parameterless MD5 CSP or SHA Managed/CSP construction in a closed plain local that computes a digest and reads inherited Hash/HashSize properties with its same-algorithm factory. Preserve property reads, clone behavior, hashing and terminal cleanup. Skip reads/hashing after cleanup, other members, escapes, captures, initialization, async/iterators and snapshots. Separate opt-in modern-.NET port; no encoding, digest format or algorithm strengthening.