Document how to re-register a Generator and keep its identity

[johnnymatthews]

One user in Discord asked whether a connection string can be updated on an existing registration or whether they had to re-register, and they were worried about creating a duplicate entry with the same Peer ID. The team's answer: re-register with the correct public IP and connection string, and keep the same private key, wallet, and Peer ID, so the whole setup doesn't have to be redone.

Their re-registration attempt then failed with:

SendICASetAndDeleteRelationship: prevDid must be non-empty and different from newDid

That error doesn't appear anywhere in the docs, and no page explains what re-registering a Generator actually does: what carries over, what gets replaced, and whether registering twice with the same Peer ID collides.

#317 is the Host version of this and it's open. It refers to a known Generator registration bug as a separate thing, so the engineering side may already be tracked. The docs side isn't.

• Confirm with the client team what re-registering a Generator does today, and whether the prevDid error is a live bug or expected behavior.
• Document the flow: when to re-register, what stays (wallet, identity keys, Peer ID), and what changes (the connection string).
• Answer the duplicate question directly: what happens when you register twice with the same Peer ID.
• If the prevDid error is still reachable, add it to the troubleshooting page.