Captures the pre-existing broken-pipe panic surfaced by the milestone fieldtest
([bug] finding): every multi-line subcommand (sweep / mc / walkforward /
runs family / generalize) panics "failed printing to stdout: Broken pipe
(os error 32)" and exits 101 when the stdout reader closes early (| head,
| less, a closed UI pane), instead of terminating cleanly. Root cause: Rust's
runtime resets SIGPIPE to SIG_IGN at startup, so a write to a closed pipe
returns EPIPE and println! panics rather than the process dying quietly.
crates/aura-cli/tests/cli_broken_pipe.rs spawns `aura sweep`, closes the stdout
read end mid-stream, and asserts no panic in stderr + exit != 101. Verified RED
(reproduces 6/6). The GREEN fix follows in the next commit.
refs #146
Brummel
c750b9fbc3