Preview Chat Action

Ghost-preview read (spec §6): the CURRENT plan for a pending place_measurements row. Auth is decide-aligned per the user ruling on 2026-08-16: only users who could decide the card may see its ghosts. This calls the resolver BELOW the decide-time recheck: live_action_state treats an empty plan as ConflictError and the decide routes flip such rows failed, but here empty is data — the ghost layer draws nothing, and the user learns the real reason at decide time. A plan that no longer resolves at all (source/target deleted), or whose stored request is malformed/stale, previews as empty for the same reason.