chore(ecstore): remove the pool-level ListObjects pagination copy (#6078)

* chore(ecstore): remove the pool-level ListObjects pagination copy

The ListObjects pagination pipeline existed in three near-copies in one file; production listing never reaches the Sets copy, which ECStore bypasses by expanding straight to per-set disks. This removes it: impl ListOperations for Sets (61 lines of pure forwarding in core/sets.rs) and the impl Sets pagination block (826 lines of inner_list_objects_v2 / list_objects_generic / inner_list_object_versions / list_path / list_merged / walk_internal in store/list_objects.rs).

Two preconditions verified before deleting rather than taken on faith: the architecture guard pins only set_disks_implements_storage_list_operations_contract, so nothing requires the Sets trait impl; and the four Sets pagination methods had no cross-file caller besides that trait impl.

The single test consumer moves to the surviving pipeline instead of being deleted: writes still go through the pool, and the listing assertion now targets the set-level implementation. It is renamed accordingly so the name still describes what it covers.

The logging guardrail's TRACE-only requirement for Sets::list_objects_v2 retires in the same diff — the wrapper it pinned no longer exists. The ECStore and SetDisks entries are untouched.

The SetDisks copy stays for now: its trait impl is guard-pinned, so replacing the duplicate pipeline behind it needs the generic helper the issue schedules for post-1.0.

Verification: cargo nextest run -p rustfs-ecstore 4020 passed; check_architecture_migration_rules.sh and check_logging_guardrails.sh pass; clippy --lib --tests -D warnings clean; make pre-commit green.

Ref rustfs/backlog#1821 (PR1).

* chore(ecstore): fold the ListObjects forwarders into the ECStore impl

store/list.rs held two thin forwarders, handle_list_objects_v2 and handle_list_object_versions, that only re-entered the inner_* implementations. The ListOperations impl now calls those directly and the file goes away.

The logging guardrail's trace_hot_spans list pinned handle_list_objects_v2 as TRACE-only; that entry is retired in the same diff, adjacent to the sets.rs entry retired by the preceding commit.

Ref rustfs/backlog#1821.

* chore(ecstore): drop the type aliases orphaned by the pagination removal

core/sets.rs declared four local type aliases — ListObjectsV2Info, ListObjectVersionsInfo, ObjectInfoOrErr and WalkOptions — used only by the pool-level pagination pipeline removed earlier in this branch. store/list_objects.rs keeps its own live copies of the same aliases.

They only surface now that #6087 removed the core module's dead_code blanket: on that older base each PR was warning-free on its own, and the combination is what exposes them. Their storage_api_contracts imports go with them.

Ref rustfs/backlog#1823, rustfs/backlog#1821.

* fix(ecstore): preserve Sets listing compatibility

crates/ecstore/tests/ecstore_contract_compat_test.rs

@@ -157,6 +157,18 @@ fn ecstore_implements_storage_list_operations_contract() {
     assert!(storage_list_operations_type_name::<ECStore>().ends_with("::ECStore"));
 }
 
+#[test]
+fn ecstore_pools_expose_storage_list_operations_contract() {
+    fn assert_contract(store: &ECStore) {
+        let future = store.pools[0]
+            .clone()
+            .list_objects_v2("bucket", "", None, None, 1, false, None, false);
+        drop(future);
+    }
+
+    let _ = assert_contract;
+}
+
 #[test]
 fn ecstore_implements_storage_multipart_operations_contract() {
     assert!(storage_multipart_operations_type_name::<ECStore>().ends_with("::ECStore"));