Reframes the SSH scope around the channel multiplexer as the decomposition
point. Each feature (forwarding, SOCKS5, SFTP) is a channel type or a consumer
of channel types, stacking on the core — each layer functional when built,
none shipped broken. Dissolves the 'massive v1' framing that produced hedging
language proposing non-functional or half-built versions.
Three developments since the initial 2026-06-25 research changed the framing:
(1) WebTransport landed as ADRs 038/040/043, grounding SSH-over-WebTransport
as a constraint (the handler must be source-agnostic about its Connection);
(2) russh's runtime abstraction (russh-util swaps tokio::spawn for
wasm_bindgen_futures on wasm32) means the SSH *client* runs in WASM when fed a
WebTransport BiStream — the browser case is real, not speculative;
(3) the http crate intersection (ALPN-stream-proxy depends on SSH handlers
being source-agnostic) is now visible and specified.
The layered build order (1-4 stream+connection+channels+exec, then 5
forwarding, then 6 SOCKS5, then 7 SFTP) doubles as the configuration surface:
each layer beyond the core is an opt-in channel type, gating on the
default-deny ACL baseline inherited from russh.
glm-5.2
78b226d31b