## Why
Guardian review evidence must remain available after a compacted thread is resumed or forked, while rolled-back or parent-local evidence must not grant authorization in a different context.
## What changed
- Store the bounded, model-invisible Guardian transcript alongside compacted rollout history and restore it from the newest surviving checkpoint during replay.
- Trim Guardian history at rollback boundaries, clearing it when the boundary has already been evicted.
- Preserve the checkpoint for user-initiated forks, but remove it when spawning a subagent so parent review evidence is not inherited.
- Keep the new rollout field optional for compatibility with existing compacted records and legacy readers.
## Testing
- Cover Guardian history across compaction, restart, paginated and pathless stores, user forks, rollback, bounded replay, serialization, and subagent forks.
GitOrigin-RevId: 6ab076d5e0c3aac4d6a41ebd50ba2b200c90213e
## Why
User messages with images larger than the Guardian history budget were skipped
entirely, removing any accompanying instructions from retained review context.
## What changed
- Retain the text and message metadata from oversized user messages while omitting
their images.
- Keep the existing behavior for other oversized history items.
## Testing
- Cover text and metadata retention, content ordering, and the integration path
with an image larger than the 4 MiB history budget.
GitOrigin-RevId: 91d99609a8d096b87d0f2b1d149f577a00dce699
## Why
Context compaction can replace original conversation items that Guardian still needs to review approval-sensitive actions.
## What changed
- Retain a bounded, chronological review history independently of the model's compacted history.
- Keep separate limits for user messages and other transcript items so tool traffic cannot evict user instructions.
- Use the retained evidence for synchronous and asynchronous Guardian transcripts, while resetting it after rollback or history reconstruction.
## Testing
- Cover retention through compaction and eviction, reset behavior after rollback, independent size limits, and asynchronous transcript construction.
GitOrigin-RevId: c5851e992820504fc18de8cfec7f6f9f1b69f316
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