Why: cross-session transcript reading needs per-conversation outbound
(allowCrossRead, default true) and inbound (crossPrivate, default false)
flags alongside the project-level gate; see the approved proposal.
Evidence: go test ./... passes with golden conversation.json regenerated
to exercise both wire fields.
Impact: additive contract fields (omitempty), wire-compatible for
existing clients that ignore unknown fields.
Refs: Agent-System-Documents proposals/2026-09-30-cross-session-reading.md
(Dev task feature/cross-session-reading).
weichen
284e8f365f