Audit and clean up dead_code annotations

- Remove stale #[allow(dead_code)] from distribution module in lib.rs
  (the module is actively used)
- Remove unused node_name_atom field from DistributionManager
  (redundant with crate::core::node::node_name_atom())
- Add targeted annotations to public API methods that are intentionally
  exposed but not used internally (native_nodes, node_type, erlang_nodes,
  node_name_atom, node_name, creation)
- Add annotations to transport infrastructure (RecvStream trait,
  QuicRecvStream, TcpRecvStream) reserved for multi-stream support
- Add annotations to test utilities (arb_pid_node2_restarted, SyncResponse)

Author: scrogson

crates/ambitious/src/distribution/manager.rs

@@ -46,7 +46,8 @@ pub struct ErlangNodeHandle {
     info: NodeInfo,
     /// Sender for outgoing ETF-encoded messages with destination info.
     tx: mpsc::Sender<ErlangOutgoingMessage>,
-    /// Last seen timestamp.
+    /// Last seen timestamp (for future heartbeat tracking).
+    #[allow(dead_code)]
     last_seen_ms: AtomicU64,
 }
 
@@ -113,8 +114,6 @@ fn current_time_ms() -> u64 {
 pub struct DistributionManager {
     /// Our node name.
     node_name: String,
-    /// Our node name as an atom.
-    node_name_atom: Atom,
     /// Our creation number.
     creation: u32,
     /// Connected native nodes by node name atom.
@@ -141,10 +140,8 @@ pub struct DistributionManager {
 impl DistributionManager {
     /// Create a new distribution manager.
     pub fn new(node_name: String, creation: u32) -> Self {
-        let node_name_atom = Atom::new(&node_name);
         Self {
             node_name,
-            node_name_atom,
             creation,
             nodes: DashMap::new(),
             addr_to_node: DashMap::new(),
@@ -413,17 +410,20 @@ impl DistributionManager {
     }
 
     /// Get list of connected native nodes only.
+    #[allow(dead_code)]
     pub fn native_nodes(&self) -> Vec<Atom> {
         self.nodes.iter().map(|r| *r.key()).collect()
     }
 
     /// Get list of connected Erlang nodes only.
     #[cfg(feature = "erlang-dist")]
+    #[allow(dead_code)]
     pub fn erlang_nodes(&self) -> Vec<Atom> {
         self.erlang_nodes.iter().map(|r| *r.key()).collect()
     }
 
     /// Get the type of a connected node.
+    #[allow(dead_code)]
     pub fn node_type(&self, node_atom: Atom) -> Option<NodeType> {
         self.node_types.get(&node_atom).map(|r| *r)
     }
@@ -619,16 +619,19 @@ impl DistributionManager {
     }
 
     /// Get our node name atom.
+    #[allow(dead_code)]
     pub fn node_name_atom(&self) -> Atom {
-        self.node_name_atom
+        crate::core::node::node_name_atom()
     }
 
     /// Get our node name.
+    #[allow(dead_code)]
     pub fn node_name(&self) -> &str {
         &self.node_name
     }
 
     /// Get our creation number.
+    #[allow(dead_code)]
     pub fn creation(&self) -> u32 {
         self.creation
     }

crates/ambitious/src/distribution/tcp_transport.rs

@@ -235,6 +235,7 @@ impl Transport for TcpTransport {
 
 /// Wrapper for receiving messages from a TCP connection.
 pub struct TcpRecvStream {
+    #[allow(dead_code)]
     connection: TcpConnection,
 }
 

crates/ambitious/src/distribution/tests.rs

@@ -33,6 +33,7 @@ fn arb_pid_node2() -> impl Strategy<Value = Pid> {
 }
 
 /// Generate a PID from node2 after restart (creation 1)
+#[allow(dead_code)]
 fn arb_pid_node2_restarted() -> impl Strategy<Value = Pid> {
     arb_pid_for_node("node2@localhost", 1)
 }
@@ -47,6 +48,7 @@ enum PgOperation {
     /// Remove all PIDs from a node (simulates disconnect)
     NodeDisconnect { node: String },
     /// Apply a sync response (simulates reconnection sync)
+    #[allow(dead_code)]
     SyncResponse {
         from_node: String,
         groups: Vec<(String, Vec<Pid>)>,

crates/ambitious/src/distribution/traits.rs

@@ -74,6 +74,7 @@ pub trait TransportConnection: Send + Sync + Clone + 'static {
 }
 
 /// A receive stream for reading additional data after the initial message.
+#[allow(dead_code)]
 #[async_trait]
 pub trait RecvStream: Send + 'static {
     /// Receive a message from this stream.

crates/ambitious/src/distribution/transport.rs

@@ -258,6 +258,7 @@ impl Transport for QuicTransport {
 }
 
 /// Wrapper around quinn's RecvStream that implements our RecvStream trait.
+#[allow(dead_code)]
 pub struct QuicRecvStream {
     inner: RecvStream,
 }

crates/ambitious/src/lib.rs

@@ -140,7 +140,6 @@ pub mod application;
 // =============================================================================
 
 /// Distribution layer for connecting Ambitious nodes.
-#[allow(dead_code)]
 pub mod distribution;
 
 /// Elixir-compatible Node API for distributed Ambitious.