Milestone-fieldtest bug (source-blind run, 2026-07-24): a member fault
on the synthetic walkforward/sweep path escapes as an uncaught panic
(exit 101, no class marker, internal source path leaked) while the
real path contains the identical fault via the #272 boundary as
aura: warning: + exit 3. Cause: the family builders in
aura-runner/src/family.rs run members bare, without the catch_unwind
containment that lives only in aura-campaign/src/exec.rs. Two RED
e2es pin the derived contract (decision log on #278): no exit 101,
a warning-marked fault line, no panic text or crates/ path on stderr,
exit 3 per the C14 partition. refs #278
claude
bd6ddf9efe