ByteStream.Feed() in UTF-8 mode permanently stalls on raw C1
control bytes (0x80-0x9F). DecodeRune returns RuneError, the loop
breaks, and the bad byte stays in the buffer forever — blocking
all subsequent input and leaking memory.
Stream.handleGround() has correct C1 handlers but they are
unreachable through ByteStream. Includes reproduction case and
suggested fix (Latin-1 fallback for invalid UTF-8 bytes).
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
GitHub Copilot