## Why
Long-lived Guardian sessions can exhaust the review model's context window. After
a rollover, a transcript delta is insufficient because the new window no longer
contains the original transcript or persistent review instructions.
## What changed
- Compact an exhausted Guardian session before submitting the next review while
respecting the review model's token-budget configuration.
- Detect whether the full transcript remains in the reviewer history. If it does
not, reset transcript and Node REPL evidence cursors so the next review replays
the complete transcript and associated image evidence.
- Restore the follow-up reminder and Node REPL policy when compaction removes
them.
## Testing
- Cover rollover both when the reviewer window is already exhausted and when a
follow-up reminder crosses the limit.
- Verify that multimodal reviews preserve the fallback buffer and replay browser
evidence after rollover.
GitOrigin-RevId: f2a02a84e1f25d15c6e2b8eddb93e2d1805449f5
bae69125df