docs(http): defer h3/WebTransport (ADR-044); browsers use WebSocket for v1

Working through the WebTransport implementation path surfaced a scope
question distinct from the hedging-as-deferral anti-pattern ADR-038 was
written to correct. Three findings drove the re-evaluation:

1. The browser bidirectional call-protocol path doesn't require
   WebTransport — WebSocket is full-duplex, EventEnvelope fits a WS
   binary message boundary cleanly, and the Dispatcher is stream-
   agnostic (ADR-012). What WebTransport gives over WebSocket (native
   multi-stream multiplexing, the ALPN-as-stream substrate) benefits the
   proxy use case, not the call protocol.
2. WebTransport is a draft standard (-07, not RFC) on an experimental
   Rust dependency stack (wtransport/h3 both self-describe as not
   production-ready). Either choice puts a draft protocol on the
   security surface of the first release.
3. The ALPN-stream-proxy (ADR-040) is speculative — its WASM parser
   consumers (browser SSH/SFTP/git clients) don't exist yet, and the
   downstream crates WebTransport deferral blocks (SSH, git, SFTP)
   expose their ALPNs natively over QUIC regardless.

This is a scope decision (per ADR-009: a decision that 'genuinely
doesn't need to be made yet because the use case isn't concrete'), not
hedging. The reversal trigger is concrete: a real deployment needing
the ALPN-stream-proxy.

ADR-038 is superseded (its anti-pattern correction stands; its specific
'h3 in scope now' decision is reversed). ADR-040 and ADR-043 are
parked, not superseded — their designs revive unchanged when WebTransport
revives, with §2 (bidirectionality) and §3 (no-PeerId overlay) of ADR-043
transferring to WebSocket for v1.

ADR-044 §5 also states the 'browser is not a peer' rationale that
ADR-034 §4 closed without arguing: peer = addressable node in the
call-protocol peer graph (stable PeerId, PeerRef::Specific-reachable,
identity stable across reconnects), not 'any endpoint that exchanges
calls during a live session.' A browser is the second but not the first
(no stable crypto identity of its own, ephemeral, not addressable from
other nodes). ADR-034 §4 and Assumption 2 are amended by reference.

The wtransport-vs-hyperium dependency question is recorded (not
resolved — WebTransport is deferred) in ADR-044 §'Research note' and
webtransport.md so the revival doesn't re-derive it: wtransport probably
isn't the right choice (axum-bridge friction — it owns its own HTTP
serving path); the hyperium stack (h3 + h3-quinn + h3-webtransport) fits
the axum integration better but its server-side WebTransport API needs
verification before commitment.

Reviewed by architecture-review subagent; all critical cross-reference
issues (ADR-034 §5 stale 'in scope' assertion, ADR-036 Context listing
h3 as implemented, webtransport.md Design Decisions table) resolved.

docs/architecture/open-questions.md

@@ -774,17 +774,19 @@ is a feature extension, not an unmade architecture decision.
 
   2. **Standalone relay service (this OQ).** A full relay — a fork of
      `iroh-relay` — that provides NAT traversal infrastructure with
-     WebTransport-based proxy as a fallback alongside websocket. This
+     WebTransport-based proxy as a fallback alongside WebSocket. This
      is a separate service, not a mode of the `h3` handler: it
      terminates the browser's WebTransport connection and forwards
      encrypted traffic to a P2P hub's Ed25519 endpoint (so the hub need
      not expose its own public X.509 cert). ADR-034 §5 recorded it in
      the h3/WebTransport bucket; ADR-038 brought h3/WebTransport into
-     scope; ADR-040 resolved the in-process proxy. This OQ is the
-     remaining scope question: does the standalone relay live in a
-     future `alknet-relay` crate (a fork of `iroh-relay` with
-     WebTransport proxy fallback) or is it out of scope for the
-     current alknet work?
+     scope (later superseded by [ADR-044](decisions/044-defer-webtransport-browsers-use-websocket.md),
+     which deferred h3/WebTransport as a scope decision — the browser
+     bidirectional path uses WebSocket); ADR-040 resolved the in-process
+     proxy (now parked per ADR-044). This OQ is the remaining scope
+     question: does the standalone relay live in a future `alknet-relay`
+     crate (a fork of `iroh-relay` with WebTransport proxy fallback) or
+     is it out of scope for the current alknet work?
 
   This is a genuine scope question, not a deferral. The relay use case
   is not yet concrete enough to commit the crate boundary — no
@@ -796,8 +798,8 @@ is a feature extension, not an unmade architecture decision.
   The relay does not change the auth model (bearer token +
   `PeerEntry.auth_token_hash`; relay is transport-only), so it does not
   block any other ADR.
-- **Cross-references**: ADR-027, ADR-030, ADR-034, ADR-038, ADR-040,
-  [webtransport.md](crates/http/webtransport.md)
+- **Cross-references**: ADR-027, ADR-030, ADR-034, ADR-038 (superseded),
+  ADR-040 (parked), ADR-044, [webtransport.md](crates/http/webtransport.md)
 
 ### OQ-39: `to_openapi` Published-Spec Versioning