foctet-wasm — browser WebTransport interop

Drives the WASM FoctetSession (datagram mode) as the handshake initiator over a real browser WebTransport against the native webtrans_datagram_split responder (tests.md §3.5). The authenticated handshake runs over a reliable bidi stream (length-prefixed control frames); the sealed application data then flows as WebTransport datagrams (one Foctet datagram frame each).

Start the native server first with the dev cert (from the repo root):
cargo run -p foctet-transport --example webtrans_datagram_split --features "runtime-tokio transport-webtrans" -- --role server --addr 127.0.0.1:4470 --tls-cert devcert/localhost.crt --tls-key devcert/localhost.key

Paste the cert hash, then press “Run test”.