Update docs for from_fn middleware

docs/roadmap.md

@@ -72,27 +72,27 @@ after formatting. Line numbers below refer to that file.
 
 ## 2. Middleware and Extractors
 
-- [ ] Develop a minimal middleware system and extractor traits for payloads,
+- [x] Develop a minimal middleware system and extractor traits for payloads,
   connection metadata, and shared state.
-  - [ ] Define `FromMessageRequest` for extractor types (lines 760-782). See
+  - [x] Define `FromMessageRequest` for extractor types (lines 760-782). See
     [`FromMessageRequest`][from-message-request] in
     [`src/extractor.rs`](../src/extractor.rs).
 
-  - [ ] Provide built-in extractors `Message<T>`, `ConnectionInfo`, and
+  - [x] Provide built-in extractors `Message<T>`, `ConnectionInfo`, and
     `SharedState<T>` (lines 792-840). `SharedState<T>` is defined in
     [`src/extractor.rs`](../src/extractor.rs#L54-L87).
 
-  - [ ] Support custom extractors implementing `FromMessageRequest` (lines
+  - [x] Support custom extractors implementing `FromMessageRequest` (lines
     842-858). Refer again to [`src/extractor.rs`](../src/extractor.rs#L39-L52).
 
   - [x] Implement middleware using `Transform`/`Service` traits.
 
-  - [x] Implement `ServiceRequest` and `ServiceResponse` wrappers
-    (lines 866-899) and introduce a `Next` helper to build the
-    asynchronous call chain. Trait definitions live in
+  - [x] Implement `ServiceRequest` and `ServiceResponse` wrappers (lines
+    866-899) and introduce a `Next` helper to build the asynchronous call chain.
+    Trait definitions live in
     [`src/middleware.rs`](../src/middleware.rs#L71-L84).
 
-    - [ ] Provide a `from_fn` helper for functional middleware.
+    - [x] Provide a `from_fn` helper for functional middleware.
     - [x] Add tests verifying middleware can modify requests and observe
       responses.
 
@@ -101,7 +101,7 @@ after formatting. Line numbers below refer to that file.
     on responses (lines 900-919). See the
     [`wrap` method](../src/app.rs#L73-L84).
 
-  - [ ] Document common middleware use cases like logging and authentication
+  - [x] Document common middleware use cases like logging and authentication
     (lines 920-935). Include a logging example using `from_fn`:
 
     ```rust

docs/rust-binary-router-library-design.md

@@ -889,39 +889,31 @@ classDiagram
     Next --> Middleware
 ```
 
-A simplified functional middleware approach, similar to
-`actix_web::middleware::from_fn` 26, could also be provided for simpler use
-cases:
+A simplified functional middleware approach uses `from_fn` so middleware can be
+written as an async function or closure:
 
 ```rust
-use wireframe::middleware::{Next, ServiceRequest, ServiceResponse}; // Hypothetical types
-
-async fn logging_mw_fn(
-    req: ServiceRequest, // Represents an incoming message/context
-    next: Next // Call to proceed to the next middleware or handler
-) -> Result<ServiceResponse, wireframe::Error> {
-    println!("Received message: {:?}", req.message_type_id());
-    let res = next.call(req).await?; // Call next service in chain
-    if let Some(response_info) = res.info() {
-        println!("Sending response: {:?}", response_info);
-    }
+use wireframe::middleware::from_fn;
+
+let logging = from_fn(|req, next| async move {
+    tracing::info!("--> received: {:?}", req.frame());
+    let mut res = next.call(req).await?;
+    tracing::info!("<-- sending: {:?}", res.frame());
     Ok(res)
-}
+});
 ```
 
 - **Registration**: Middleware would be registered with the `WireframeApp`
   builder:
 
   ```rust
   WireframeApp::new()
-     .wrap(LoggingMiddleware::new())
-     .wrap(AuthMiddleware::new(/* config */))
-      // For functional middleware:
-      //.wrap(wireframe::middleware::from_fn(logging_mw_fn))
+     .wrap(from_fn(|req, next| async move { /* auth */ next.call(req).await }))
+     .wrap(logging)
   ```
 
-  Middleware is typically executed in the reverse order of registration for
-  incoming messages and in the registration order for outgoing responses.
+  The last middleware registered (`logging` above) runs first on incoming
+  messages and last on outgoing responses.
 
 - **Use Cases**: