test+docs: prepublish hardening from review (failure paths, doc hygiene)

Coverage:
- CF-002: demux skipped-bytes budget teardown test (268 MiB skip in-memory;
  a budgetless demux wedges in the 17th skip, the real one tears down) and
  the skip-hits-EOF arm (truncated oversized payload ends the loop).
- CF-001: retryable CONNECTION_CLOSED pinned for subscribe write failures
  in both stream modes and single-stream publish request-frame failures;
  non-retryable INTERNAL pinned for mid-publish failures in both modes
  (deterministic FailOnFlushN write half).
- Gateway: invoke_sink with with_deadline(None) completes a slow sink.

Docs:
- Fix broken intra-doc link on lib.rs's feature-gated gateway mention
  (rustdoc warned on default-feature builds).
- Re-point 40 src/ references from the old alknet mono-repo ADR numbering
  (049/050/052/065/070/074/092) to this crate's numbering
  (021/011/034/007/008/009/005); drop into_sub_streams references
  removed by ADR-035.

Verification: 565 default / 582 all-features (8 new), clippy -D warnings
on default/gateway/all-features/wasm32, fmt clean, rustdoc warning-free
on default and all-features, publish dry-run clean. Consumer-facing API
continuity 0.1.1 -> 0.2.0 verified by compiling an API-surface probe
against both versions.

src/protocol/dispatch.rs

@@ -382,7 +382,7 @@ impl Dispatcher {
         connection: Arc<CallConnection>,
         stream: crate::core::types::BiStream,
     ) {
-        // `stream` is a `BiStream` (ADR-092) — `AsyncRead + AsyncWrite + Send
+        // `stream` is a `BiStream` (ADR-009) — `AsyncRead + AsyncWrite + Send
         // + Unpin`. Split into the read and write halves the call protocol's
         // frame reader/writer consume. The split is the stdlib idiom; no
         // per-handler wrapper.
@@ -441,7 +441,7 @@ impl Dispatcher {
     /// for `Ok`, `call.error` for `Err`). On natural stream end (the stream
     /// returned `None` without the last item being an `Err`), write a
     /// `call.completed` frame. An `Err` envelope is terminal — the stream
-    /// ends after it and we do NOT write `call.completed` (ADR-049 §6).
+    /// ends after it and we do NOT write `call.completed` (ADR-021 §6).
     ///
     /// If a frame write fails the pump stops early; the stream is dropped on
     /// return, releasing the handler's resources via `Drop` (ADR-016). A
@@ -1477,7 +1477,7 @@ mod tests {
         );
     }
 
-    // --- streaming dispatch branch (ADR-049 §6) ---------------------------
+    // --- streaming dispatch branch (ADR-021 §6) ---------------------------
 
     fn subscription_spec(name: &str, acl: AccessControl) -> OperationSpec {
         OperationSpec::new(