Separate child local completion before propagating replication confirmation counts #3341

Draft #3187 retains the current production boundary: the context count belongs to the root and txnForContext does not copy it to later database links. If private counts are manually assigned to both parent and child, the parent currently waits on the child's complete commit promise, including remote confirmation. A failed parent confirmation can therefore remain pending behind a child remote waiter after their local commits landed.

Before enabling multi-link count propagation, separate the child's local completion from its remote confirmation and decide which confirmation failure is surfaced once all local work settles. Preserve prompt local failures and prevent confirmation failure from aborting a pending local commit. Add held-promise regressions for both parent/child failure orders on real stores.

Entry condition: any change copying the count in txnForContext or otherwise enabling confirmations on later production links must settle this ordering first. Current public producers do not assign those child counts; this is scoped future work confirmed by the framing recheck.

Review-Deferral: 9c03bc90cc60188b severity=major category=reliability

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