dex: hotfix for 2025-01-18 chain halt (alternative) (#4994)

## Describe your changes

This commit fixes the chain halt that occurred on 2025-01-18 at block
3093519.

### What happened (short version):

A transaction was submitted that contained both `PositionClose` and
`PositionWithdraw` actions for the same position `P`, which had been
auto-closed by the DEX. In `DeliverTx`, the `PositionClose` action
queued the position for closure by ID, and the `PositionWithdraw` action
checked that the position state was closed and then updated it to
Withdrawn. Later, in `EndBlock`, the queued position closure was
executed. The position state was not Opened or Closed, triggering an
assertion.

### Why it happened

- Mempool tx checking does not execute end block so this didn't get
filtered out
- The position closure method allows the position closure to be a no-op,
but only for positions in the closed state
- Because the position was withdrawn, the state was unexpected

### What this does

Avoid queueing the position for closure unless it is Opened.

(cherry picked from commit f7f780d)

crates/core/component/dex/src/component/action_handler/position/close.rs

@@ -2,9 +2,8 @@ use anyhow::Result;
 use async_trait::async_trait;
 use cnidarium::StateWrite;
 use cnidarium_component::ActionHandler;
-use penumbra_proto::{DomainType as _, StateWriteProto as _};
 
-use crate::{component::PositionManager, event, lp::action::PositionClose};
+use crate::{component::PositionManager, lp::action::PositionClose};
 
 #[async_trait]
 /// Debits an opened position NFT and credits a closed position NFT.
@@ -22,15 +21,7 @@ impl ActionHandler for PositionClose {
         // lose the ability to do block-scoped JIT liquidity, where a single
         // transaction opens and closes a position, keeping liquidity live only
         // during that block's batch swap execution.
-        state.queue_close_position(self.position_id);
-
-        // queue position close you will...
-        state.record_proto(
-            event::EventQueuePositionClose {
-                position_id: self.position_id,
-            }
-            .to_proto(),
-        );
+        state.queue_close_position(self.position_id).await?;
 
         Ok(())
     }

crates/core/component/dex/src/component/position_manager.rs

@@ -211,10 +211,37 @@ pub trait PositionManager: StateWrite + PositionRead {
     }
 
     /// Queues a position to be closed at the end of the block, after batch execution.
-    fn queue_close_position(&mut self, id: position::Id) {
-        let mut to_close = self.pending_position_closures();
-        to_close.push_back(id);
-        self.object_put(state_key::pending_position_closures(), to_close);
+    async fn queue_close_position(&mut self, id: position::Id) -> Result<()> {
+        tracing::debug!(
+            ?id,
+            "checking current position state before queueing for closure"
+        );
+        let current_state = self
+            .position_by_id(&id)
+            .await
+            .expect("fetching position should not fail")
+            .ok_or_else(|| anyhow::anyhow!("could not find position {} to close", id))?
+            .tap(|lp| tracing::trace!(prev_state = ?lp, "retrieved previous lp state"));
+
+        if current_state.state == position::State::Opened {
+            tracing::debug!(
+                ?current_state.state,
+                "queueing opened position for closure"
+            );
+            let mut to_close = self.pending_position_closures();
+            to_close.push_back(id);
+            self.object_put(state_key::pending_position_closures(), to_close);
+
+            // queue position close you will...
+            self.record_proto(event::EventQueuePositionClose { position_id: id }.to_proto());
+        } else {
+            tracing::debug!(
+                ?current_state.state,
+                "skipping queueing for closure of non-opened position"
+            );
+        }
+
+        Ok(())
     }
 
     /// Close all positions that have been queued for closure.