captureAll

Map a run of events to LogRecords and export them as one write turn.

The batched counterpart of capture, and the drain's entry point since #2194: the exporter's fixed per-turn cost — one CRDT append pass, one CBOR encode, one segment write — is paid once for the whole run instead of once per line.

Every per-event decision is unchanged and still per-event. The self-capture exclusion, the CaptureConfig.minLevel gate and the trace/sampling gate each drop their own events out of the run before any record is built; the survivors are exported together. Durability is unchanged — nothing is held back waiting for the run to grow (see WarpLogRecordExporter.export).

Returns null when the run produced no records at all — either it was empty or every event was dropped — so a caller can tell "nothing to do" from an export result.