## Why
Pre-turn compaction runs before incoming input is recorded, so failures could leave an accepted prompt out of conversation history. Reporting the error before prompt hooks finish also lets clients steer follow-up input into a turn still preserving its prompt.
## What changed
Record input and run prompt hooks on every pre-turn compaction failure. Defer local and remote compaction error events to `run_turn`, after prompt preservation completes, while retaining the remote error prefix.
## Testing
Extend the remote compaction output-validation test to trigger automatic compaction and assert that the prompt is emitted before the error, saved exactly once, and followed by no additional model request. Retain the assertion that usage is recorded for invalid compaction output.
GitOrigin-RevId: ab7ccb259836c084173e0e81dbbd4c610e95a6c8
ee93abb690