Keep Uint8Array identity while validating the native buffer: reject author proxies and resizable/growable storage, distinguish detached fixed buffers from detached resizable buffers, and reject shared storage unless the declaration explicitly permits it. Add derive-level allow_shared support and mark TextEncoder.encodeInto’s destination according to Encoding IDL. Depends on the shared native buffer introspection foundation; conversion tests cover direct locals, optional/sequence fields, shared policy and getter exceptions.
