docs: implementation plan (TTY precedents folded in); task decomposition (17 tasks)

Plan updated with the alknet-tty findings: the drainer pattern
(single ordered writer) makes outbound chunk-boundary parsing sound;
TestStdinSink's try_send→Full→Pending is the inbound backpressure
precedent; OQ-01(a) now cites the reference.

Task graph (taskgraph-validated, 17 tasks, 6 generations, no cycles):
- tasks/server/: core-types, auth, healthz-decoy, adapter
- tasks/gateway/: dispatch, routes, publish
- tasks/websocket/: byte-adapter (research POC), upgrade-session, overlay-ops
- tasks/adapters/: from-openapi, from-jsonschema, to-openapi, from-wss, mcp
- tasks/client/: http-host
- tasks/infra/: integration-suite (phase 4)

Critical path runs through server core → adapter → WS session →
overlay tests → integration suite. High-risk tasks are the three WS
tasks, de-risked by the ws-byte-adapter POC blocking upgrade-session.

tasks/server/adapter.md

@@ -0,0 +1,45 @@
+---
+id: server-adapter
+name: HttpAdapter — ProtocolHandler with hyper over BiStream
+status: pending
+depends_on: [server-core-types, server-auth, server-healthz-decoy]
+scope: moderate
+risk: medium
+impact: component
+level: implementation
+tags: [server, phase-1]
+---
+
+## Description
+
+Port the `HttpAdapter` (`ProtocolHandler` for `http/1.1` + `h2`) from
+`/workspace/@alkdev/alknet/crates/alknet-http/src/server/adapter.rs`,
+adapted to alkcall's shapes: `handle()` receives a `Connection`
+(alkcall::core::types), takes the `BiStream` from `accept_bi()`, wraps
+with `TokioIo`, drives hyper's http1/http2 connection builder against
+the axum `Router` (built once at construction, `with_decoy` /
+`with_extra_routes` builders per ADR-046). Branch on
+`connection.remote_alpn()`. Leave a route slot for the WS upgrade
+(wired in the websocket tasks).
+
+## Acceptance Criteria
+
+- [ ] `HttpAdapter::new/h2/for_alpn` + `with_decoy` + `with_extra_routes` ported
+- [ ] `ProtocolHandler` impl drives hyper over the BiStream; returns on connection close
+- [ ] Router merges extra routes; default surface wins collisions
+- [ ] Integration test: full HTTP request/response cycle over `tokio::io::DuplexStream` → `Connection::from_bidi` → adapter
+- [ ] `cargo test` passes; feature gates `h2`/`http1` both compile
+
+## References
+
+- docs/architecture/http-server.md (§Running axum over a bidirectional stream)
+- docs/architecture/decisions/002-protocol-handler-trait.md
+- alkcall: `core::types::Connection::accept_bi` returns joined `BiStream` (alkcall ADR-005)
+
+## Notes
+
+> Agent fills during implementation.
+
+## Summary
+
+> Agent fills on completion.