* fix(engine): look up satisfied durable entries by primary key

The old join filtered branch and node after reading every entry for the task.

* fix(engine): prune durable entry lookups to the task partition

Pass each task's inserted_at into ListSatisfiedEntries and plan with those values so daily partitions that do not contain them are not locked.

* fix(engine): bound durable entry lookups by task inserted_at range

Replace the timestamp array with min/max bounds so the btree does not re-sort the array on every index rescan, and return to the plain primary-key join with materialized inputs instead of a lateral subquery.

* simple feedback

* drop plan stuff

* fix(engine): pass task inserted_at on the operator action

The DAG operator reads inserted_at from the assigned action instead of looking the task up. Keep the satisfied-entry external id typed as uuid so sqlc still emits uuid.UUID.

* fix: signatures