0.1 — state at the second security review

The build as it stood when second-review.md was written (2026-08-13): WebRTC and
QUIC transports, GEK-HMAC handshake proof, Ed25519 admin challenges, node
sovereignty, P2P crypto material.

Tagged because it is what that review describes, not because it was fit to hold
private data: six critical and seven high findings were open against it, and the
review says so on its first page. The node served every private group in
plaintext over an unauthenticated HTTP port (C1), and an active hub could be
handed any group key through the key directory it controlled (H3).