## Why
Guardian authorization reviews need host-verified `request_user_input` answers to
remain aligned with thread history across compaction, resume, and rollback.
## What changed
- Record verified question-and-answer pairs in retained thread context when
`GuardianThreadContext` is enabled, and source both local and delegated Guardian
review evidence from that context.
- Preserve complete answer records within the evidence budget. Mark authorization
context incomplete when records are unavailable or oversized, and defer cached
fast approvals in that case.
- Keep the existing runtime-only answer path for threads that do not enable the
thread-owned context.
## Testing
- Cover answer retention through compaction and resume, removal after rollback,
source-call eviction, oversized answers, delegated review evidence, and legacy
behavior.
GitOrigin-RevId: 01f6f4541515434a0d00fdde318ff59f2f8bd2eb