## Why
Async Guardian requests include retained user instructions even when complete copies are already present in the same request's transcript.
## What changed
- Include retained source metadata and order labels in async user transcript entries.
- Omit retained instructions when the current transcript contains the same complete source revision. Keep ordering guidance in every async sample and never rely on previous samples for deduplication.
- Preserve retained originals when transcript copies are incomplete or lack source metadata.
## Testing
Extend retained-instruction tests to cover async deduplication, preservation of originals without complete source proof, and budget protection. Update async scorer expectations for source order labels and deduplicated instructions.
GitOrigin-RevId: 7029731b296d2342eea4ad74ffa9d3447578d83e