Local administration surface for the user allowlist, dispatched before the
server flag set parses os.Args. It opens the SQLite store directly with no
network or auth: running on the bus host is trusted by design, which is how
the first admin is seeded (breaking the chicken-egg of needing an admin to
add an admin). Validates that sign-pub is a 32-byte Ed25519 key in hex and
tolerates the sign-pub positional appearing before or after --db.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>