Function create_invite 

pub fn create_invite(
    identity: &Identity,
    network_id: &str,
    invitee_fingerprint: Option<String>,
    ttl_hours: u64,
    invite_password: &str,
) -> BpResult<String>

Generate a signed + password-encrypted invite token for network_id.

Parameters

• identity — The inviter’s loaded identity (must have joined network_id).
• network_id — Network the invitee will be joining.
• invitee_fingerprint — Optional: restrict the token to one specific invitee.
• ttl_hours — How long the token is valid (e.g. 24).
• invite_password — Shared out-of-band with the invitee (never stored).

Returns

A hex-encoded blob that can be passed to redeem_invite.