Fix relevant AI code review suggestions

These are for an older PR: #8741

https://gist.github.com/david-crespo/a84474b432090316fa3efcb41335cc24

Author: andrewjstone

trust-quorum/src/coordinator_state.rs

@@ -211,13 +211,14 @@ impl CoordinatorState {
             #[expect(unused)]
             CoordinatorOperation::CollectLrtqShares { members, shares } => {}
             CoordinatorOperation::Prepare { prepares, .. } => {
-                for (platform_id, (config, share)) in
-                    prepares.clone().into_iter()
-                {
+                for (platform_id, (config, share)) in prepares.iter() {
                     if ctx.connected().contains(&platform_id) {
                         ctx.send(
-                            platform_id,
-                            PeerMsgKind::Prepare { config, share },
+                            platform_id.clone(),
+                            PeerMsgKind::Prepare {
+                                config: config.clone(),
+                                share: share.clone(),
+                            },
                         );
                     }
                 }
@@ -241,7 +242,6 @@ impl CoordinatorState {
             } => {}
             CoordinatorOperation::CollectLrtqShares { members, shares } => {}
             CoordinatorOperation::Prepare { prepares, prepare_acks } => {
-                let rack_id = self.reconfigure_msg.rack_id();
                 if let Some((config, share)) = prepares.get(&to) {
                     ctx.send(
                         to,

trust-quorum/src/node.rs

@@ -568,6 +568,16 @@ impl Node {
             return;
         }
 
+        if !config.members.contains_key(ctx.platform_id()) {
+            error!(
+                self.log,
+                "Received Prepare when not a member of configuration";
+                "from" => %from,
+                "prepare_epoch" => %config.epoch
+            );
+            return;
+        }
+
         // We always save the config and share if we haven't committed a later
         // configuration. If we have seen a newer `Prepare`, it's possible
         // that that configuration will not commit, and the latest committed
@@ -594,7 +604,10 @@ impl Node {
             );
         }
         // If we are coordinating for an older epoch, then we should stop
-        // coordinating. This epoch will never commit.
+        // coordinating. The configuration at this epoch will either never
+        // commit, or has already committed without us learning about it from
+        // Nexus. In either case the rest of the system has moved on and we
+        // should stop coordinating.
         if let Some(cs) = &self.coordinator_state {
             if msg_epoch > cs.reconfigure_msg().epoch() {
                 // This prepare is for a newer configuration than the one we are