Per-tunnel server session for Connect-UDP-Bind (draft-ietf-masque-connect-udp-listen-11) over HTTP/1.1.

Sibling of masque_udp_bind_server_session (h2/h3); the wire format above the transport is identical, so capsule and payload logic is reused unchanged. Only the transport plumbing differs: h1 takes ownership of the upgraded TLS socket via h1:accept_upgrade/3 and reads / writes capsules directly on it through h1_capsule:encode/2 and h1_capsule:decode/1.