## Why
`node_repl` screenshots are nested tool results and do not appear in the parent
conversation history, so Guardian v2 transcript image collection could miss
them.
## What changed
- Allow Guardian v2 to enable bounded, thread-scoped `node_repl` image capture
when transcript images are configured.
- Add retained `node_repl` screenshots to review requests when transcript
sources include tool outputs, while deduplicating images and keeping them out
of the parent turn input.
## Testing
- Add an integration test covering screenshot capture without the synchronous
Guardian transcript feature flags and verifying that screenshots stay out of
the parent request.
GitOrigin-RevId: 5f70c5f2e80389aa8b2a286c3b7f9b1104865486
jif
9b9b614b02