Get Pipeline Annotations

Batch-compute the deferred pipeline annotations for a chosen set of deals.

The counterpart to GET /pipeline?defer_annotations=true: that endpoint skips _annotate_client_contacts / _annotate_commercial_states / _annotate_latest_activities for a fast first paint; the web kanban calls this afterward, in priority batches, to stream those fields in. Deal ids outside the caller's org are silently dropped rather than erroring — the caller is just naming rows it already saw on its own board.