- Check both jwt and cryptography in MSTEAMS_AVAILABLE guard so
partial installs fail early with a clear message instead of at runtime
- Add aclose() to test FakeHttpClient so stop() won't crash
- Move MSTEAMS.md into README.md following the same details/summary
pattern used by every other channel
- Note in README that validateInboundAuth defaults to false
PyJWT and cryptography are optional msteams deps; they should not be
bundled into the generic dev install. Tests now skip the entire file
when the deps are missing, following the dingtalk pattern.
