Reverts a360d0b. A separate process group let an overflow kill the curl
behind a profile script, but Ctrl+C then reached only idx and left a
stalled transfer running (Pullfrog review on #55). Cancellation is the
common path; on overflow, curl still ends on its next write to the
closed pipe, and the error returns at once either way.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01V3syn2fN2LNo5pvTSqc6eh