[F53 partial] enable #![warn(missing_docs)] on consumer crates

mxaccess + mxaccess-compat now carry #![warn(missing_docs)] at the
crate root. Every public item has at least a one-line doc comment
(struct fields, enum variants, trait methods all covered).

Touched items:
- mxaccess::lib: DataChange fields, SecurityContext fields,
  TransportKind variants, TransportCapabilities fields,
  RecoveryEvent variants + their inner fields, SessionOptions
  fields, the full Error / ConnectionError / AuthError /
  ProtocolError / ConfigError / SecurityError taxonomy + nested
  fields, Transport trait method docs.
- mxaccess-compat::lib: DataChangeEvent / BufferedDataChangeEvent /
  WriteCompleteEvent / OperationCompleteEvent fields.

Protocol crates (codec, rpc, galaxy, nmx, callback, asb,
asb-nettcp) deliberately left without the lint per F53's strategy
paragraph — their consumers (mxaccess + mxaccess-compat) already
document the surfaces they re-export, and forcing one-liners on
every transport-internal item adds noise without consumer value.

Verification:
- `RUSTDOCFLAGS="-D warnings" cargo doc --workspace --no-deps` clean.
- `cargo test --workspace` (824 tests) green.
- `cargo clippy --workspace --all-targets -- -D warnings` clean.

design/followups.md F53 marked partially resolved.

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

rust/crates/mxaccess-compat/src/lib.rs

@@ -50,6 +50,7 @@
 //! live-trigger work.
 
 #![forbid(unsafe_code)]
+#![warn(missing_docs)]
 
 use std::collections::{HashMap, VecDeque};
 use std::pin::Pin;
@@ -73,12 +74,20 @@ use tokio_stream::wrappers::BroadcastStream;
 /// `MxNativeDataChangeEvent` (`MxNativeCompatibilityServer.cs:6-13`).
 #[derive(Debug, Clone)]
 pub struct DataChangeEvent {
+    /// LMX server handle that produced this event.
     pub server_handle: i32,
+    /// Item handle within `server_handle` whose value changed.
     pub item_handle: i32,
+    /// Decoded value payload.
     pub value: MxValue,
+    /// Legacy 16-bit OPC quality.
     pub quality: u16,
+    /// Wire-recorded timestamp (Windows FILETIME-derived).
     pub timestamp: SystemTime,
+    /// Richer category-model status (complements `quality`).
     pub status: MxStatus,
+    /// `true` when the event was emitted while a `recover_connection`
+    /// attempt was in flight.
     pub is_during_recovery: bool,
 }
 
@@ -90,13 +99,21 @@ pub struct DataChangeEvent {
 /// capture proves multi-sample bodies real.
 #[derive(Debug, Clone)]
 pub struct BufferedDataChangeEvent {
+    /// LMX server handle that produced this event.
     pub server_handle: i32,
+    /// Item handle within `server_handle`.
     pub item_handle: i32,
+    /// `MxDataType` discriminator for the carried values.
     pub mx_data_type: i16,
+    /// Sample values — length 1 per R2's single-sample verdict.
     pub values: Vec<MxValue>,
+    /// Per-sample legacy 16-bit OPC qualities. Same length as `values`.
     pub qualities: Vec<u16>,
+    /// Per-sample timestamps. Same length as `values`.
     pub timestamps: Vec<SystemTime>,
+    /// Per-sample richer-category status. Same length as `values`.
     pub statuses: Vec<MxStatus>,
+    /// `true` when the event was emitted during recovery.
     pub is_during_recovery: bool,
 }
 
@@ -104,9 +121,13 @@ pub struct BufferedDataChangeEvent {
 /// `MxNativeWriteCompleteEvent` (`cs:15-19`).
 #[derive(Debug, Clone)]
 pub struct WriteCompleteEvent {
+    /// LMX server handle that issued the original write.
     pub server_handle: i32,
+    /// Item handle the write was targeted at.
     pub item_handle: i32,
+    /// Per-write completion statuses (one per `MXSTATUS_PROXY` slot).
     pub statuses: Vec<MxStatus>,
+    /// `true` when the write completed while recovery was in flight.
     pub is_during_recovery: bool,
 }
 
@@ -117,9 +138,13 @@ pub struct WriteCompleteEvent {
 /// once the trigger is captured.
 #[derive(Debug, Clone)]
 pub struct OperationCompleteEvent {
+    /// LMX server handle the operation belongs to.
     pub server_handle: i32,
+    /// Item handle the operation was targeted at.
     pub item_handle: i32,
+    /// Per-operation statuses.
     pub statuses: Vec<MxStatus>,
+    /// `true` when the event was emitted during recovery.
     pub is_during_recovery: bool,
 }