Function rebind_v2_alias 

pub fn rebind_v2_alias(
    cfg: &HubConfig,
    alias: &str,
    from: &str,
    to: &str,
) -> LinkResult<Value>

Explicitly replace one mutable alias binding after the operator reviews the exact deleted/re-created brain ids. Canonical checkpoints are never removed or rewritten, so old history remains pinned and the new brain establishes its own independently verified trust chain.