uplift: add customlogs package from evm repositories

vms/evm/customlogs/log_ext.go

@@ -0,0 +1,21 @@
+// Copyright (C) 2019-2025, Ava Labs, Inc. All rights reserved.
+// See the file LICENSE for licensing terms.
+
+package customlogs
+
+import "github.com/ava-labs/libevm/core/types"
+
+// FlattenLogs converts a nested array of logs to a single array of logs.
+func FlattenLogs(list [][]*types.Log) []*types.Log {
+	numLogs := 0
+	for _, logs := range list {
+		numLogs += len(logs)
+	}
+
+	// Pre-allocate slice with exact capacity
+	flat := make([]*types.Log, 0, numLogs)
+	for _, logs := range list {
+		flat = append(flat, logs...)
+	}
+	return flat
+}