Unit 10: honest stubs, substrate mode docs, spec-doc renumbering

- C-10: channel/control returns channel:control_not_implemented (OQ-39)
- C-11: channel/resources/subscribe returns channel:resources_not_implemented (OQ-40)
- C-14: adapter.rs doc comments accurately describe in-line-only substrate
  mode; QUIC-native multi-stream deferred to alknet (OQ-41)
- C-15: ChannelClient code already clean (stale open_channel_stream ref
  removed in prior unit); no code changes needed
- C-26: spec docs updated to post-047 model (per-ALPN open ops, no
  ChannelDirection, no ResourceEntry.access); stale alknet ADR refs
  (071/075/076/078/079/080/093/094) renumbered to alkcall equivalents
  (034/035/039/040/041/042/043)
- OQs 39-41 filed in open-questions.md

Verification: cargo test (483 passed), cargo clippy (clean),
cargo fmt (clean), cargo doc (no warnings)

docs/architecture/channels-wire.md

@@ -130,6 +130,13 @@ yields repeatedly — each stream is a channel, and the header provides
 `channel_id` correlation. Same code path, same wire format, same handler
 experience. See ADR-034 §substrate modes (as amended by ADR-035), ADR-039.
 
+**Implementation status:** the in-line substrate mode is implemented
+(single bidi stream, header-demuxed N channels). The QUIC-native
+multi-stream substrate (accept remaining bidi streams, read headers off
+each) is deferred to the downstream alknet crate (OQ-41). The wire
+format and demux loop are correct for both substrates; only the outer
+`accept_bi()` loop is missing.
+
 ## Wire-level invariants (REQ-CH-01, 02, 04, 05)
 
 The de-risk POC (`docs/research/alknet-channels/poc-summary.md` §Issues
@@ -238,9 +245,9 @@ payload — is decided; the *function surface* is not.
 
 | Phase | Mechanism | Reference |
 |-------|-----------|-----------|
-| Open | `channel/open` call operation on channel 0; responder allocates `channel_id`, returns it | ADR-037 |
+| Open | Per-ALPN open op (`channels/<alpn>/sub` or `channels/<alpn>/pub`) on channel 0; connection owner allocates `channel_id`, returns it | ADR-047 §3, §5 |
 | Data | chunks with `channel_id` routed to reassembly buffers; handler sees a `BiStream` | this doc, [channels-connection.md](channels-connection.md) |
-| Control (out-of-band) | `channel/control` call operation on channel 0 | ADR-037 |
+| Control (out-of-band) | `channel/control` call operation on channel 0 (deferred — OQ-39) | ADR-037 |
 | Close | `channel/close` call operation on channel 0; data chunks flushed before close | ADR-037, REQ-CH-06 |
 
 ### REQ-CH-06: exit-chunk-before-close ordering (generalizes ADR-055)
@@ -270,8 +277,8 @@ All design decisions are documented as ADRs in [decisions/](decisions/).
 
 | ADR | Decision | Summary |
 |-----|----------|---------|
-| [071](decisions/071-channels-wire-format.md) | channels Wire Format | 8-byte chunk header (amended by ADR-035); channels layer has no `stream_type` concept; one-way door |
-| [093](decisions/093-channels-pure-channel-multiplexing.md) | channels Pure Channel Multiplexing | The umbrella decision: 8-byte header, no `stream_type`, `into_sub_streams` removed, `BiStream`-only, TTY always 5-byte |
+| [034](decisions/034-channels-wire-format.md) | channels Wire Format | 8-byte chunk header (amended by ADR-035); channels layer has no `stream_type` concept; one-way door |
+| [035](decisions/035-channels-pure-channel-multiplexing.md) | channels Pure Channel Multiplexing | The umbrella decision: 8-byte header, no `stream_type`, `into_sub_streams` removed, `BiStream`-only, TTY always 5-byte |
 
 ## Open Questions
 
@@ -289,14 +296,12 @@ Key questions affecting this doc:
   header, no `stream_type`)
 - ADR-035: channels pure channel multiplexing (the umbrella decision that
   amends ADR-034/074/077)
-- ADR-052: alknet-tty wire format (the 5-byte format carried
-  transparently in the channels payload)
 - ADR-036: channel 0 pre-negotiated
 - ADR-037: channel lifecycle operations
 - ADR-040: backpressure, channel limits, ID reuse
+- ADR-047: openable ALPNs are operations (per-ALPN open ops dissolve
+  the generic `channel/open`)
 - `docs/research/alknet-channels/poc-summary.md` §POC Target 1, §Issues
   Surfaced #4-#6 (REQ-CH-01, 02, 04)
 - `docs/research/stream-unification/findings.md` — the research that
-  surfaced the 8-byte format decision
-- `crates/alknet-tty/src/wire.rs` — the 5-byte format implementation
-  (carried transparently in the channels payload)
+  surfaced the 8-byte format decision