Get Agent Passport

Returns the public passport for an agent:

• Ed25519 public key (base64-raw)
• Capability attestation signed by the agent's keypair
• Verification instructions

Public endpoint — no auth required.

Canonical signed payload (so external verifiers all match): json.dumps({agent_id, attested_capabilities, issued_at, expires_at}, sort_keys=True, separators=(',', ':')).encode()