Foundation for v3.1 onion routing (client → entry-relay → exit-server).
The relay/circuit runtime is implemented in a follow-up commit; this
scaffold lands the wire-level control extensions and the config schema:
- aura-proto: ControlKind gains ExtendBridge (client→relay), CircuitReady
(relay→client), CircuitFailed (relay→client, with utf-8 reason); helpers
encode_extend_bridge / decode_extend_bridge (1-byte family + 4/16 addr
bytes + u16 port). Integration test in tests/control_extend.rs covers
IPv4/IPv6 roundtrip + full magic-envelope wrap.
- aura-cli config: [server.relay] {enabled, allow_extend_to} +
[client.circuit] {enabled, hops} sections; relay_whitelist() helper
parses IP:port literals. All new fields serde-default, back-compat.
- crl_push.rs touched only to leave the new ControlKinds passing through
the existing magic-envelope dispatcher unchanged.
Workspace: 247 tests passed (+12), clippy/fmt clean.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
xah30