consumer: Socks5ChannelSession (CONNECT) — teardown ownership + e2e suite

- Socks5ChannelSession::connect: open_channel(OP_SOCKS5_OPEN, {},
  SOCKS5_ALPN) then the forked client typestate's use_stream path
  over the channel BiStream (POC #1's fit); post-reply the session
  is the raw byte pipe (0 B framing)
- Target construction via ToTargetAddr: IP-string forms parse to IP
  targets, domain form passes through unresolved (ADR-012)
- split() borrowed halves (SplitPipe) / into_inner() owned pipe
  (TakenInner — the session rides along as the teardown owner);
  channel_id() for correlation
- Teardown ownership (alktunnels ADR-005 posture): Drop sync-reaps
  the adopted entry (teardown_channel is sync; Drop cannot await) +
  the pipe drop EOFs the producer pump structurally; close() is the
  graceful path (write-half shutdown, then reap); the in-stream
  refusal tears the channel down in connect (teardown-at-birth —
  no phantom channel); no Clone (compile_fail doctest)
- Error surface: open failures are the typed SocksOpenError reasons
  (ADR-049 §4); a refused target is the RFC reply code through
  SocksSessionError::Rfc (consumer.md §Error surface)
- Harness: the consumer-side topology (wire_consumer_side[_with] —
  the consumer dials with a real ChannelClient; the producer accepts
  with the real registration) + witnessing_echo_dial; the
  allow(dead_code) attr rides the alktunnels harness posture
- tests/consumer-connect.rs: 9 e2e tests — echo round-trip + CF-006
  witness, target forms at the dial seam (ADR-012), refused dial →
  typed RFC error + no phantom channel, FORBIDDEN open → typed open
  error + no session, drop teardown + connection health, half-close
  EOF semantics, into_inner pairing, Send shape

Verified: cargo test (219 green incl. the compile_fail doctest),
clippy --all-targets -D warnings, fmt --check,
check/clippy --target wasm32-unknown-unknown

tasks/implementation/core-consumer-connect.md

@@ -1,7 +1,7 @@
 ---
 id: implementation/core-consumer-connect
 name: "Core — consumer half: Socks5ChannelSession (CONNECT) + e2e tests"
-status: pending
+status: completed
 depends_on: [implementation/core-producer-connect]
 scope: narrow
 risk: low
@@ -70,8 +70,51 @@ consumer.rs`, adapted to the crate's params/error surface):
 
 ## Notes
 
-> To be filled by implementation agent
+> Filled by the implementation agent (2026-09-23):
+
+- The session shape is exactly the POC's, adapted to the crate
+  surface: `Socks5Stream::use_stream(bidi, None, Config::default())`
+  over `BiStream::from_joined(recv, send)`, then `request(TCPConnect,
+  target)`. `Config::default()` is the no-auth posture (the
+  `skip_auth` knob stays internal to the fork; the identity seam is
+  the open op's, CF-005/CF-006 — no RFC-facing auth on this path).
+- `split()` returns borrowed halves (`tokio::io::split` over a
+  `&mut Socks5Stream<BiStream>`; the `SplitPipe` type alias), not
+  owned ones: the session keeps teardown ownership for every shape,
+  including the split-driven one. The owned path is `into_inner()`
+  (`TakenInner { session, inner }` — the session rides along as the
+  teardown owner).
+- Refusal teardown: an in-stream refusal (Rfc error) tears the
+  adopted channel down inside `connect` before the error returns
+  (teardown-at-birth; the phantom-channel property, tested both
+  sides). The producer's own handler-exit teardown races the
+  consumer's — the leak-check probe polls past that race.
+- Drop is the sync-reap posture (`teardown_channel` is sync;
+  `Drop` cannot await) + the structural EOF of the dropped pipe; the
+  graceful path is `close()` (write-half shutdown first, then reap).
+- Harness: added the consumer-side topology (`wire_consumer_side[_with]`
+  — the consumer dials with a real `ChannelClient`; the producer
+  accepts with the real registration) plus `witnessing_echo_dial`
+  (the dial-witness target-form probe). The `allow(dead_code)` attr
+  rides the alktunnels harness posture (each test binary compiles the
+  harness and uses a different subset).
+- No `Clone` is compile-asserted by the doctest; a runtime probe
+  pins `Send` (the `Clone` bound itself is the doctest's job).
 
 ## Summary
 
-> To be filled on completion
+Implemented `Socks5ChannelSession` (CONNECT) in `src/consumer.rs` —
+`connect`/`channel_id`/`split`/`into_inner`/`close` + `Drop` teardown
+ownership and the `SplitPipe`/`TakenInner` companions — with the
+typed error surface (`SocksOpenError` for opens, the RFC reply code
+through `SocksSessionError::Rfc` for refused targets) and
+teardown-at-birth on the in-stream refusal path. E2E suite
+(`tests/consumer-connect.rs`, 9 tests over the new consumer-side
+harness topology): echo round-trip + CF-006 witness, target forms
+(IP-string parses / domain passes through — ADR-012, wire-observed
+at the dial), refused dial → typed RFC error + no phantom channel,
+FORBIDDEN open → typed open error + no session, drop teardown +
+connection health, half-close EOF semantics, `into_inner` pairing,
+and the no-`Clone`/`Send` compile shape (the `compile_fail` doctest
+pins `!Clone`). Verification: `cargo test` (219 incl. the doctest),
+clippy `-D warnings` (all targets), fmt, and both wasm checks clean.