Function nip55_perms_json 

pub fn nip55_perms_json() -> String

Render the pairing permissions JSON: blanket encrypt/decrypt plus one {"type":"sign_event","kind":K} per signed kind. Never includes get_private_key — same policy as crate::signer::VECTOR_NIP46_PERMS; the whole point of an external signer is that the identity nsec never leaves it.