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/core/README.md

@@ -10,19 +10,16 @@ dispatch. Every handler crate depends on `alknet-core` for
 `ProtocolHandler`, `Connection`, `AuthContext`, `IdentityProvider`, and
 config types. The endpoint (`AlknetEndpoint`, `HandlerRegistry`) lives
 in [`alknet-endpoint`](../endpoint/README.md) (ADR-083 Amendment
-2026-07-15; `EndpointError` is removed — both variants were vestigial);
-core does not carry the accept-loop runner or its transport deps
-(quinn, iroh, rcgen, rustls-acme). `Connection::from_quinn` /
-`from_iroh` are in core's `types.rs` as shared constructors (gated on
-core's `quinn` / `iroh` features).
+2026-07-15); core does not carry the accept-loop runner or its
+transport deps (quinn, iroh, rcgen, rustls-acme).
+`Connection::from_quinn` / `from_iroh` are in core's `types.rs` as
+shared constructors (gated on core's `quinn` / `iroh` features).
 
 `ConnectionCredentials` and `RemoteIdentity` live in `alknet-core` (per
 ADR-091) — the transport-level credential bundle consumed by the dial
 (`alknet-client`) and by server-side transport construction. There is no
-call-protocol credential bundle: `CallCredentials` is removed (ADR-091
-Am. 2026-07-17 — its `auth_token` field had no reader; `auth_token` is
-a per-request payload field on `call.requested`, not a transport
-credential).
+call-protocol credential bundle; `auth_token` is a per-request payload
+field on `call.requested`, not a transport credential.
 
 ## Documents