The canonical implementation is `whatsapp_suite/`. Edit it rather than the encoded payload in `whatsapp.py`. Synthetic fixtures belong in `tests/`; never use captured messages or contacts as fixtures.
Use Python 3.11+ and Node.js for the complete offline suite. Optional requirements are in `requirements-whatsapp-optional.txt`. Run source tests, rebuild with `python build_whatsapp_bundle.py`, and run the portable tests before committing. Check that unchanged inputs produce the same bundle hash.
Native sources are in `native/`; existing verified runtime DLLs are in `whatsapp_suite/assets/`. Changing native code requires rebuilding for Windows x64, updating asset hashes and conducting explicit build-specific live validation. Run `native\build.cmd` and `native\build_webhook.cmd` from an x64 MSVC Native Tools prompt to build the helpers (Windows SDK required). The recipes reproduce compilation; native PE bytes are not promised to be bit-identical across toolchain versions or timestamps. Update the Python helper hashes and `docs/runtime-assets.json` after a native rebuild. The Python builder packages existing DLLs and does not compile them.
Document compatibility changes and distinguish synthetic checks from live checks. Keep send operations explicit, fixed-recipient guards intact, and default tests free of live side effects. Inspect `git diff --cached` and the tracked file list before publication.
