fix: Address Codex review feedback

- Remove early return in start_subscription_request that prevented
  optimal location nodes from subscribing
- Remove empty test that provided no actual coverage

The early return issue was a critical bug that prevented the k_closest
fix from working in the auto-subscribe path (PUT/GET operations). When
a node was at optimal location, it would skip subscription entirely
rather than trying alternative peers.

These issues made it past testing because:
1. The integration tests were removed due to CI environment constraints
2. The empty test gave false confidence about coverage
3. The auto-subscribe path wasn't explicitly tested

Author: sanity

crates/core/src/operations/mod.rs

@@ -308,26 +308,9 @@ impl<T> From<SendError<T>> for OpError {
 
 /// If the contract is not found, it will try to get it first if the `try_get` parameter is set.
 async fn start_subscription_request(op_manager: &OpManager, key: ContractKey) {
-    // Check if we are the optimal location for this contract
-    // If we are and no other peers are suitable, skip subscription for now
-    // TODO: In the future, still find next-best peers for redundancy (issue #1793)
-    let own_location = op_manager.ring.connection_manager.own_location();
-    let closest = op_manager
-        .ring
-        .closest_potentially_caching(&key, [&own_location.peer].as_slice());
-
-    if closest.is_none() {
-        // No other peers available for caching
-        // Check if we should be caching this locally
-        if op_manager.ring.should_seed(&key) {
-            tracing::debug!(
-                %key,
-                "Skipping subscription - node is optimal location and no other peers available"
-            );
-            return;
-        }
-    }
-
+    // Always try to subscribe, even if we're at optimal location
+    // The k_closest_potentially_caching logic in subscribe::request_subscribe
+    // will find alternative peers if needed
     let sub_op = subscribe::start_op(key);
     if let Err(error) = subscribe::request_subscribe(op_manager, sub_op).await {
         tracing::warn!(%error, "Error subscribing to contract");

crates/core/src/operations/subscribe/tests.rs

@@ -31,26 +31,6 @@ fn test_subscription_response_generates_host_result() {
     }
 }
 
-/// Test that k_closest_potentially_caching is used for finding peers
-/// This verifies the fix for nodes at optimal location not being able to subscribe
-#[test]
-fn test_uses_multiple_peer_candidates() {
-    // This test would require mocking the OpManager and ring structures
-    // For now, we verify the code structure uses k_closest_potentially_caching
-    // with k=3 in the actual implementation
-
-    // The actual implementation in request_subscribe should use:
-    // op_manager.ring.k_closest_potentially_caching(key, EMPTY, 3)
-    // instead of closest_potentially_caching
-
-    // Similarly, in the message handler for ReturnSub with subscribed: false,
-    // it should use:
-    // op_manager.ring.k_closest_potentially_caching(key, &skip_list, 3)
-
-    // This is a compile-time verification that the method exists
-    // Actual runtime testing requires the full integration test
-}
-
 /// Test that subscription state transitions correctly
 #[test]
 fn test_subscription_state_transitions() {