720344cfba
Backends that omit per-item done events on a successful completion (anomalyco/opencode#37159) caused an announced function call to be silently dropped: the turn ended with output == [] and the tool never executed. Track calls announced via output_item.added, accumulate argument deltas, and settle still-pending calls from accumulated state at a successful terminal event. output_item.done stays authoritative. Mirrors anomalyco/opencode#43575.