## What changed
- Add the optional `active_permission_profile` field to `TurnContextItem` to record the built-in or named profile that produced the effective permission profile.
- Populate the field when serializing a turn context while preserving compatibility with records where it is absent.
## Testing
- Add coverage verifying that turn-context serialization stores the active permission profile.
GitOrigin-RevId: d69142ab1b26595ab406235f89818ef41370e963