[DRAFT] Add initial implementation of parent close policy transfer task

[awln-temporal]

What changed?

Implementation of parent close policy transfer tasks. Parent close policies are applied for each child workflow when the parent is closed. During task generation when the workflow execution is closing, one parent close policy task will be created per child workflow, assuming the parent close policy is not to abandon the child workflow.

On the active task executor, the parent close policy task is handled by calling the corresponding Cancel/Terminate workflow API on the history client.

On the standby task executor, verification that the child workflow is closed or deleted is done by checking its mutable state. If the child workflow is not found, we need to defer to the state on the Source (active) cluster. The child workflow may not have been replicated.

Rollout Procedure

To roll this feature out safely, the following steps will be done:

1. Have two consecutive releases that include this PR. (Feature is not safe to rollback once turned on)
2. On the second release that includes this PR, perform a global Dynamic Config rollout of history.enableParentClosePolicyTransferTasks = true
3. Monitor metrics: Operation TransferActiveTaskParentClosePolicy for count and successful handling of tasks.

Why?

System worker handling parent close policy tasks can lead to task dropping.

How did you test it?

• built
• run locally and tested manually
• covered by existing tests
• added new unit test(s)
• added new functional test(s)

Potential risks

TODO: Update section.