Issue: TSMT insert fails to migrate leaf nodes to depth 48

Issue: TSMT insert fails to migrate leaf nodes to depth 48: a task in LegoFlow-SWE (Harbor dataset). When inserting a key-value pair into the Tiered Sparse Merkle Tree (TSMT), if the key shares a 16-bit or 32-bit prefix with an existing key already stored at depth 16 or 32, the tree does not…