pub fn active_signer() -> Result<ActiveSigner, String>Expand description
Resolve the active session’s signer.
Fails CLOSED on identity mismatch: a remote-signer account’s vault holds its client keypair, whose pubkey is not the identity. Signing with it emits wrong-identity events that self-reject on every reader (AuthorMismatch), so erroring here surfaces the misconfiguration instead of a silently undeliverable send.