tasks: Phase 2 decomposition — 12-task dependency graph for v1

tasks/architecture/:
- oq-promotion-sync (planning): back-pointers from the phase-0 ledger
  + AGENTS.md to the promoted OQ tracker (the convergence checklist's
  final half)
- oq-tn-14-tracker: the Safe-Exit external-trigger tracker task for
  OQ-TN-14 (unix/stdio placement; [external-trigger, deferred-oq],
  risk trivial, level research per the two-halves rule)

tasks/tunnels/ (the implementation graph, 8 generations):
- crate-init: module skeleton per overview.md's module map
- params: TunnelParams + open-op spec (ADR-001 wire-stable surface)
- wire-codec: frame_datagram/DatagramReader + the 8 POC-pinned test
  families (ADR-003)
- producer-open-op: establisher (dial, plan flow R-01) + pump handler
  (pump_bidi inline R-02) + registration; POC-ported integration tests
- consumer-session: TunnelSession (open/adopt, data planes, teardown
  matrix — ADR-005); generalizes the reverse POC's ReverseTunnel
- producer-listen: the listen establisher + AcceptQueue contract
  (ADR-004 shape 2)
- local-socket-halves: the local feature (TCP/UDP/unix halves
  functions; truncation fail-loud per OQ-TN-13; unix ships per
  OQ-TN-14's lean-yes, stdio deferred)
- review-core-crates: review-injection point before the downstream
  tasks build on the high-risk producer/consumer shapes
- end-to-end-suite: 6 suites / >=20 tests consolidating both POC
  suites against the public API (the spec's executable form)
- review-impl: the phase-gate review (wire/API/conventions/docs sync;
  findings doc per the alkhttp/alkcall house pattern)

Graph verified with taskgraph: 12 tasks valid, no cycles, 8
generations; critical path = oq-promotion-sync -> crate-init ->
params -> wire-codec -> producer-open-op -> consumer-session ->
review-core-crates -> review-impl; risk concentrated in the two
session tasks (both POC-validated); parallel groups available at
generations 1 and 6

tasks/tunnels/crate-init.md

@@ -0,0 +1,91 @@
+---
+id: tunnels/crate-init
+name: Initialize the alktunnels module skeleton (params, wire, producer, consumer, error)
+status: pending
+depends_on: [architecture/oq-promotion-sync]
+scope: narrow
+risk: low
+impact: project
+level: implementation
+tags: [scaffold, crate-init]
+---
+
+## Description
+
+Convert the alktunnels scaffold crate into the real module skeleton per
+`docs/architecture/overview.md` §Module Map. The crate already exists
+(Cargo.toml with alkcall 0.7.0, the wasm-clean tokio subset, licenses,
+`lib.rs` stub); this task adds the module structure the subsequent tasks
+fill in.
+
+### Module skeleton
+
+```rust
+// src/lib.rs
+//! alktunnels — arbitrary bidirectional tunnels over alkcall channels.
+//! (crate docs per overview.md §What — the two-paragraph shape)
+
+pub mod error;
+pub mod params;
+pub mod wire;
+
+pub mod producer;
+pub mod consumer;
+
+// Public API surface: re-exports filled in by subsequent tasks (convention 16).
+```
+
+- `src/error.rs` — `TunnelError` (thiserror; convention 2) + the typed
+  open-error surface re-exported from alkcall (`ChannelOpenError`,
+  `establishment_reason`-shaped helper). Skeleton only; filled by
+  `tunnels/params` and `tunnels/consumer-session`.
+- `src/params.rs` — `TunnelParams {resource, substrate}` +
+  `Substrate` enum (`tcp | udp | unix`) + `tunnel_open_spec()` builder +
+  `TUNNEL_OPEN_SCOPE`/`OP_TUNNEL_OPEN`/`TUNNEL_ALPN` constants. Skeleton
+  with type definitions; the schema builder + tests land in
+  `tunnels/params`.
+- `src/wire.rs` — the codec module doc (ADR-003 summary + bast.md
+  pointer); skeleton for `frame_datagram`/`DatagramReader`/
+  `DatagramCodecError`, filled by `tunnels/wire-codec`.
+- `src/producer.rs` — module doc (producer.md summary); skeleton for
+  `tunnel_open_spec` wiring, `register_tunnel_openable`, the establisher
+  shape, the pump handler — filled by `tunnels/producer-open-op` +
+  `tunnels/producer-listen`.
+- `src/consumer.rs` — module doc (consumer.md summary); skeleton for
+  `TunnelSession` — filled by `tunnels/consumer-session`.
+
+### Keep in place / verify
+
+- Cargo.toml: alkcall 0.7.0 pin, the wasm-clean tokio subset, the empty
+  `[features]` table (the `local` feature is added by `tunnels/local-socket-halves`).
+- `bytes`, `serde`, `serde_json`, `thiserror`, `tracing`, `futures` stay;
+  drop `async-trait` IF the skeleton confirms no trait is needed (ADR-004 —
+  it likely is not; note the decision in Summary if dropped).
+- The default crate stays wasm-clean: `cargo check --target
+  wasm32-unknown-unknown` must pass at every task in this graph
+  (convention 4; the structural guard).
+
+## Acceptance Criteria
+
+- [ ] `src/lib.rs` declares `error`, `params`, `wire`, `producer`,
+      `consumer` with doc comments; public API re-exports listed (empty
+      bodies fine)
+- [ ] Every skeleton module compiles (`cargo check` clean)
+- [ ] `cargo clippy --all-targets -- -D warnings` clean
+- [ ] `cargo fmt --check` clean
+- [ ] `cargo check --target wasm32-unknown-unknown` passes
+- [ ] No comments in code beyond doc comments (convention 1)
+
+## References
+
+- docs/architecture/overview.md (module map, feature gates)
+- docs/architecture/decisions/004-no-backend-trait.md (module placement)
+- AGENTS.md conventions 1/2/4/15/16
+
+## Notes
+
+> Agent fills during implementation.
+
+## Summary
+
+> Agent fills this on completion.