docs(adrs): reconcile WS-03 browser data-channel promise (ADR-067/048)

Record the v1 cut for browser-opened data channels over WS (review-001
WS-03): the design (ADR-067) stands; only the wiring is deferred.

- open-questions.md: add OQ-05 (deferred(scope: v1 cut)) with gap
  detail and deferred scope
- ADR-067: dated status amendment + v1-cut note at the data-channel
  step; References point to OQ-05
- ADR-048: dated reconciliation note — overlay bidirectionality is
  decided design, not a v1 implementation commitment
- websocket.md: status notes on §"Data channels for browsers" and
  upgrade step 7
- task review-001-ws-data-channel-decision: completed, Summary filled

Verification: taskgraph validate (38 tasks OK); cargo doc --no-deps
(pre-existing warnings only).

docs/architecture/websocket.md

@@ -89,6 +89,8 @@ route on `HttpAdapter`'s router. The handler:
 7. Data channels (1..N) route per the deployment's openable-ALPN
    registrations; the browser opens them via the per-ALPN open ops on
    channel 0 (alkcall ADR-047), the same mechanism any consumer uses.
+   *(Deferred wiring, v1 cut — see [OQ-05](open-questions.md);
+   step 6, channel 0, is all v1 implements.)*
 
 The **default upgrade path is `/alk/channels`** (was `/alknet/call` in
 the alknet design). The path must not collide with the reserved
@@ -198,6 +200,11 @@ before ACL). This is alkcall ADR-017's model; see also
 
 ### Data channels for browsers
 
+> **Status (2026-08-29):** decided design, deferred wiring — the v1 WS
+> path installs channel 0 only; browser data-channel opens are not yet
+> wired (review-001, WS-03; [OQ-05](open-questions.md)). The mechanism
+> below is the contract the deferred wiring implements.
+
 A browser opens a data channel exactly as any channels consumer:
 
 1. Calls the per-ALPN open op on channel 0