## What changed
Add `model_post_turn_compact_threshold_percent` to trigger compaction after a final response when context usage reaches the configured percentage of the usable window or an existing auto-compaction limit. Accept values from `0` to `100`; omitted or zero disables the feature.
Skip post-turn compaction when input is pending, the turn is cancelled, or token-budget mode is enabled. Disable it for approval reviewers to avoid delaying approval completion, and record a distinct `PostTurn` analytics phase.
Buffer local post-turn summaries until compaction succeeds and require a nonempty assistant summary before replacing history. Log compaction failures without failing the completed turn, while still propagating interruptions and turn aborts.
GitOrigin-RevId: b616994175829bd83b5d7974f95dabb042a39a89