Starting from a tree with nothing in it, stand up a second complete, self-contained Solidity project: write the build configuration and directory layout from scratch, and implement one small pure library that verifies a Merkle inclusion proof against a root, together with a test suite that exercises it hard — valid proofs at several depths, single-leaf trees, proofs of the wrong length, sibling ordering, and leaves the tree never contained.

Commit anything the build needs into the diff as ordinary files, never as a submodule or a fetched pointer. Keep the scope to one library and its tests. The verifier re-runs the build and the suite offline with no network and no credentials, so the suite must compile and actually examine the library rather than passing vacuously.