pub(crate) fn require_node_key_file(path: &str)Expand description
Refuses to sign an operator-only op with a key file that does not already exist.
load_key creates a key file when absent, which is right for an
agent minting its own identity and wrong here: a typo’d path would
silently mint a fresh key, and the node would reject the submission as
an unknown signer rather than as the mistake it is.