btree->min_unpublished_durable_ts is maintained only for basic operations at transaction commit; WT_TXN_OP_TRUNCATE_ROW/COL and WT_TXN_OP_REF_DELETE skip the hook, as does the step-up drain's truncate replay (__layered_apply_truncate_to_stable).

Consequence: a stable constituent awaiting publication whose only unpublished content is truncate tombstones — e.g. a reused constituent carrying prior-era rows plus follower truncates replayed at step-up — passes the unpublished-data drop guard and is discarded on close, losing tombstones a checkpoint was obligated to persist.

Found while fixing WT-18347, which added the hook for drained row updates only.