Function barrier_recovery_finalize_decision 

pub fn barrier_recovery_finalize_decision(
    has_pending: bool,
    current_coordinator_epoch: Option<i32>,
    frozen_coordinator_epoch: i32,
    targets_valid: bool,
) -> BarrierRecoveryFinalizeDecision

Decide whether an interrupted injection can be finalized conservatively.

A valid finalization has a current coordinator at or above the frozen coordinator epoch and at least one valid target partition. The recovery adapter supplies no observed marker offsets, so this decision can only authorize a partial cut.