Slice 3 of the #319 retirement. The campaign leg's --override injects a
single-value axis over the named bound param into every strategy entry —
after intrinsic validation, before the referential gate, so an unknown
path speaks validate_campaign_refs' existing did-you-mean prose and a
kind mismatch its existing fault; collision with a document-declared axis
refuses (an override overrides a bound value, never an axis, exit 2).
The stored bytes and the recorded campaign_id stay those of the original
document; the audit record of an override is the raw member manifests.
The walk-forward zero-trade aura: note: diagnostic now has a campaign-
path producer call (present_campaign per-cell), so it survives the
quintet's removal at today's strength.
refs #319
claude
696d7fe59a