Reconcile observed checkout work onto the current turn's traces.
Inspect backend checkouts without blocking the event loop.
Compare successful observations, including newly created checkouts.
Inspect candidate checkouts on the backend; optional failures may propagate.
Return current-turn roots, or None when no scoped trace is active.
Repository identity and opaque non-content evidence of checkout work.
Keep sibling invocation roots alive until the thread starts another turn.
Observe backend work and backfill only the initiating user turn.
Each observing tool call compares a snapshot taken after it runs with the newest earlier snapshot from the same turn, so a probe before the call is only needed when its arguments reach paths outside checkouts the turn has already inspected. A checkout first seen without an earlier inspection of the same paths only becomes a baseline, so preexisting dirt is not credited. Repeated probe failures back off and then disable probing for the session.
