docs(architecture): remove removed-thing remnants from spec docs

Spec docs should describe WHAT IS, not WHAT WAS. ADRs and OQ files are
historical records by design and are left alone; the ADR-index Status
column records ADR status (stable fact). What changed in the specs:

- API code blocks no longer list removed methods. ChannelClient::connect_quic
  (channel-client.md) and CallClient::connect (client-and-adapters.md) are
  gone from the impl blocks; surrounding prose describes the current
  from_connection / spawn_dispatch primary + AlknetClient dial shape.
- Amendment (ADR-093): stream_types field is removed blockquotes dropped
  from channel-client.md and channel-operations.md (the code already
  reflects the current state).
- Historical is-removed / reversed-by / amended-by prose rewritten to
  current state across channels crate, call crate, hub, tls, core,
  endpoint, client READMEs, and the top-level README/overview.
- Dropped the EndpointError — removed subsection from endpoint/README.md
  (the type doesn't exist anymore, so it shouldn't have a subsection).
- Replaced stale connect() references in flow descriptions with the dial
  (in AlknetClient) since connect() is no longer a method.
- Removed strikethrough ADR-028 / from_jsonschema-clause rows from
  client-and-adapters.md and operation-registry.md ADR tables.
- Rewrote the ADR-066 update blockquote in operation-registry.md to
  describe FromJsonSchema's current shape.

19 files modified, net -116 lines. No ADRs or OQ files touched.

docs/architecture/crates/hub/README.md

@@ -287,8 +287,8 @@ another hub (A) is a client from A's perspective. The dial needs a
 client-side TLS config (`TlsClientConfig`, ADR-087) for the outbound
 connection's `rustls::ClientConfig` (verifier selection per ADR-034:
 fingerprint pin for the worker's known key). The dial path mirrors the
-`from_connection` primary (ADR-080; `ChannelClient::connect_quic` is
-removed per ADR-089 §5 — the dial lives in `AlknetClient`):
+`from_connection` primary (ADR-080; the dial lives in `AlknetClient`,
+ADR-089):
 
 ```rust
 impl Hub {
@@ -296,9 +296,8 @@ impl Hub {
     /// connection. Transport-agnostic — the caller (or a transport
     /// helper) produces the `Connection`. This is the primary path;
     /// `connect_quic_worker` (a hub-level convenience, distinct from
-    /// the removed `ChannelClient::connect_quic` per-protocol
-    /// constructor — ADR-089 §5) and future `connect_tcp_tls_worker`
-    /// are conveniences over it.
+    /// the per-protocol dial in `AlknetClient`) and future
+    /// `connect_tcp_tls_worker` are conveniences over it.
     pub async fn dial_worker_connection(
         &self,
         connection: Connection,
@@ -791,7 +790,7 @@ into `CallAdapter::with_aggregated_env`.
 | Peer-graph routing model | [ADR-029](../../decisions/029-peer-graph-routing-model.md) | Peer-keyed overlays, `PeerRef` routing, `AccessControl`-based peer auth |
 | PeerEntry and Identity.id | [ADR-030](../../decisions/030-peerentry-and-identity-id-decoupling.md) | `PeerId` = `Identity.id` = `PeerEntry.peer_id` (stable) |
 | Three peer roles | [ADR-034](../../decisions/034-outgoing-only-x509-and-three-peer-roles.md) | Hub = role-3 `PeerEntry` (mixed fingerprints); browsers not peers; bearer-token identity over TCP/WebTransport |
-| ChannelClient — transport-agnostic | [ADR-080](../../decisions/080-channelclient.md) | `from_connection` primary; `connect_quic` removed per ADR-089 §5 (dial extracted to `AlknetClient`); the dial path the hub uses |
+| ChannelClient — transport-agnostic | [ADR-080](../../decisions/080-channelclient.md) | `from_connection` primary; dial in `AlknetClient` (ADR-089) — the dial path the hub uses |
 | Channels transport-agnostic | [ADR-071](../../decisions/071-channels-wire-format.md) | Substrate modes; `Connection::from_stream`/`from_bidi` (ADR-065) — the substrate the hub relays |
 | TCP+TLS as first-class owned transport | [ADR-083](../../decisions/083-endpoint-as-accept-loop-runner.md) | `with_tcp_tls(listener, acceptor)` — TCP+TLS is owned by the endpoint, not a sibling loop; supersedes ADR-010 Am. 1 |
 | Channel 0 pre-negotiated | [ADR-072](../../decisions/072-channel-0-pre-negotiated-call.md) | Channel 0 = `alknet/call`; the `CallAdapter` runs here |
@@ -841,8 +840,7 @@ See [open-questions.md](../../open-questions.md) for full details.
 ## References
 
 - [channel-client.md](../channels/channel-client.md) — `ChannelClient`
-  (`from_connection` — the take-over; `connect_quic` removed per
-  ADR-089 §5, dial now via `AlknetClient`)
+  (`from_connection` — the take-over; dial via `AlknetClient` per ADR-089)
 - [channels-adapter.md](../channels/channels-adapter.md) —
   `ChannelsAdapter`, `ChannelManager`, the accept path
 - [channel-operations.md](../channels/channel-operations.md) —