Ordinary stderr redirection and static glob arguments disable streaming pipelines

Follow-up to #453: adding 2>/dev/null or an unquoted static glob makes an otherwise eligible pipeline fully buffered. For example, rg -l NEEDLE /src | head -n 1 can stop discovery, whereas the stderr-redirection form reads the complete tree.

Two separate fixes are appropriate: allow ordinary fd 2 file redirection through the existing redirection owner; allow static glob arguments through the existing word-expansion owner. Preserve redirection errors, argument order, quoted patterns and pipefail. No new shell expansion implementation.