docs: typed-output direction set — russh-sftp shape, (a) vs (b) fork
- branch 1 output contract targets typed Rust structs (no Value
materialization): the kernel-fusion move, alkminer precedent
- russh-sftp protocol-type shape as target (plain structs, field
order = decode order, shared cursor codec core)
- fork: (a) serde-derive + generic Deserializer (interop) vs
(b) generated direct codecs (zero overhead, the 72ns shape)
- follow-up #1 sharpened: typed-output POC renders Packet both ways,
benchmarks against the raw-decode baseline
glm-5.3-flash
a52c8a6b37