docs(arch): unweld CallClient from QUIC — spawn_dispatch primary, connect convenience (ADR-017 Am. 2026-07-13)

Same fix as ADR-080 (ChannelClient) applied to the call crate. The
existing code already had the right structure — spawn_dispatch is not
feature-gated (transport-agnostic), connect is #[cfg(feature = "quinn")]
— but the docs inverted the framing: connect was 'primary,' spawn_dispatch
was 'lower-level.' That welding masked the call protocol's
transport-agnosticism (ADR-012 EventEnvelope; ADR-065 from_stream/from_bidi
accept any AsyncRead + AsyncWrite).

Changes:
- client-and-adapters.md: reframe spawn_dispatch as the transport-
  agnostic primary constructor (one-way door), connect as the QUIC
  convenience (two-way door, feature-gated on quinn). Mirror the
  from_connection / connect_quic pattern from ADR-080/channel-client.md.
  Fix all 'QUIC-backed' / 'over QUIC' / 'opens a QUIC connection' framing
  to be transport-agnostic. Fix from_call description, adapter location
  map, exchange-of-operations example, Constraints section.
- call-protocol.md: 'runs over QUIC bidirectional streams' → 'runs over
  any ordered, reliable bidirectional stream.' Fix stream model, stream
  lifecycle (connection drop / stream reset now list all transports,
  not just QUIC). Fix CallConnection.connection doc comment.
- operation-registry.md: FromCall provenance comment 'QUIC forwarding
  stub' → 'call-protocol forwarding stub.' Fix from_call description.
- call README.md: fix client-and-adapters.md description, fix design
  principle #11 framing.
- ADR-017: add Amendment (2026-07-13) documenting the spawn_dispatch /
  connect reframe, mirroring ADR-080's amendment.
- overview.md, architecture README: update ADR-017 and
  client-and-adapters.md table summaries.
- OQ-015, OQ-007: fix 'opens QUIC connections' / 'bidirectional QUIC
  streams' framing in resolution text.

No code changes — spawn_dispatch and connect already exist with the
right feature-gate structure. This is a documentation reframe.

docs/architecture/README.md

@@ -148,7 +148,7 @@ adapter location map is now consistent: all HTTP-backed adapters
 | [crates/call/README.md](crates/call/README.md) | draft | alknet-call crate index |
 | [crates/call/call-protocol.md](crates/call/call-protocol.md) | draft | CallAdapter, hand-rolled EventEnvelope framing (no irpc — ADR-064), stream model, PendingRequestMap, bidirectional calls, streaming subscribe example |
 | [crates/call/operation-registry.md](crates/call/operation-registry.md) | draft | OperationSpec, Handler, OperationRegistry, AccessControl, capability injection, service discovery (hand-rolled, no irpc) |
-| [crates/call/client-and-adapters.md](crates/call/client-and-adapters.md) | draft | CallClient (outbound connection opener), from_call, OperationAdapter trait, adapter location map, no-env-vars invariant, exchange-of-operations pattern (from_jsonschema moved to alknet-http per ADR-066) |
+| [crates/call/client-and-adapters.md](crates/call/client-and-adapters.md) | draft | CallClient (transport-agnostic `spawn_dispatch` primary, `connect` QUIC convenience — ADR-017 Am. 2026-07-13), from_call, OperationAdapter trait, adapter location map, no-env-vars invariant, exchange-of-operations pattern (from_jsonschema moved to alknet-http per ADR-066) |
 | [crates/http/README.md](crates/http/README.md) | draft | alknet-http crate index |
 | [crates/http/overview.md](crates/http/overview.md) | draft | Crate purpose, two roles (server + client host), dependencies, adapter location map |
 | [crates/http/http-server.md](crates/http/http-server.md) | draft | HttpAdapter for h2/http1.1 + WebSocket upgrade route, axum over QUIC, Bearer auth, stealth, /healthz |