Function handle_well_known_did 

pub async fn handle_well_known_did(
    host: Option<String>,
    node: Arc<TapNode>,
    event_bus: Arc<EventBus>,
    max_agents: usize,
) -> Result<impl Reply, Infallible>

Handler for /.well-known/did.json requests.

Maps the hostname from the HTTP request to a did:web DID. If an agent with that DID exists in the node’s agent registry, returns the DID document. If not, creates a new agent with fresh keys and returns the document.

The DID document includes the DIDComm messaging service endpoint and the agent’s public keys.