## Why
Guardian reviews need the original user instructions even when compaction or
transcript selection removes them from the active conversation window.
## What changed
- Capture complete user messages in host-owned retained context and include them
as ordered authorization evidence alongside verified answers.
- Omit oversized instructions atomically and emit an explicit incomplete-evidence
notice instead of exposing a potentially misleading partial permission.
- Mark user messages inherited by forked agents so they remain model-visible
without becoming child-local authorization.
## Testing
- Cover retained instructions across compaction, resume, rollback, and agent
forks, including oversized evidence and legacy context behavior.
GitOrigin-RevId: 97122509d818c90d2f87c6a1b29c99c05ad0316e
9c4253ffc1