[F42] cargo doc --workspace --no-deps clean (0 warnings)

Fix all 33 rustdoc warnings across the workspace:

- Unresolved intra-doc links: rewrite [`name`] → either backtick text
  (when not actually a link) or fully-qualified `[Type::method]` /
  `[crate::module::name]` form. Affected: mxaccess-codec
  (asb_variant, item_control, metadata_query, observed_write_template,
  reference_handle, write_message), mxaccess-rpc (pdu), mxaccess-nmx
  (client), mxaccess-asb-nettcp (nmf), mxaccess-callback (exporter),
  mxaccess (asb_session, session, lib).
- Bracket-text being interpreted as link refs (e.g. `body[17]` →
  `` `body[17]` ``).
- Private-item references in public docs (CALLBACK_BROADCAST_CAPACITY,
  recover_connection_core, mxvalue_to_writevalue) reduced to
  backtick-text since they aren't part of the public API.

`RUSTDOCFLAGS="-D warnings" cargo doc --workspace --no-deps` now
exits clean. Workspace 759 tests pass; clippy clean.

Defers `#![warn(missing_docs)]` lint to a future pass — the cleanup
target is the broken-link warnings, which are signal; missing-docs
would surface hundreds of low-priority public-item gaps that are out
of scope for this F-number.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

rust/crates/mxaccess-nmx/src/client.rs

@@ -88,7 +88,7 @@ pub enum NmxClientError {
 
     /// The metadata's `(mx_data_type, is_array)` pair has no LMX wire
     /// encoding (e.g. arrays of `ElapsedTime`, scalars of
-    /// `ReferenceType`). Returned by [`NmxClient::resolve_write_kind`]
+    /// `ReferenceType`). Returned by [`GalaxyTagMetadata::resolve_write_kind`]
     /// helpers when the caller asks for a kind that
     /// [`mxaccess_codec::MxValueKind::for_data_type`] rejects.
     /// Mirrors the `ArgumentOutOfRangeException` paths in the .NET
@@ -530,7 +530,7 @@ impl NmxClient {
     }
 
     /// `INmxService2::RemoveSubscriberEngine` (opnum 8). Mirrors
-    /// `cs:137-147`. Same wire shape as [`add_subscriber_engine`].
+    /// `cs:137-147`. Same wire shape as [`Self::add_subscriber_engine`].
     ///
     /// # Errors
     /// Transport or codec.