Task #2 completed in `/usr/local/src/reticulum/LXMF`.

Created:

- `tools/make_test_vectors.pl`
- `tools/verify_examples.pl`
- `tools/LXMF/MessagePack.pm`
- `tools/README.md`
- `examples/lxmf_message_minimal.hex`
- `examples/lxmf_message_stamped.hex`
- `examples/lxmf_message_vectors.json`

The dependency-free Perl tooling verifies:

- Fixed hash/signature positions
- Payload order and MessagePack types
- Message ID calculation
- Optional stamp exclusion from message ID and signature input

Validation passed:

```text
Reticulum umsgpack byte-for-byte cross-check passed
All LXMessage test-vector checks passed.
```

The vectors regenerate deterministically. Signature bytes are documented placeholders; Ed25519 validation is not claimed. `SPEC.md` was not created or modified.