The previous commit removed cache_media_bytes from teams/adapter.py's import
block but left one bare call at the Bot-Framework image path — a NameError
that the surrounding 'except Exception' swallowed, so every BF image
attachment was silently dropped (ruff F821). Route it through
cache_media_bytes_async like the file's two other sites.
Same bug class at the sites the sweep did not reach:
- buzz _download_attachment / _localize_inbound_media: cache_media_bytes
called from async methods → cache_media_bytes_async.
- photon _dispatch_inbound: _normalize_binary_payload (base64 decode +
cache write of possibly multi-MB payloads) ran on the loop → closure made
async, helper offloaded via asyncio.to_thread.
Tests: cover cache_media_bytes_async (thread-id + kwarg forwarding);
teams/buzz tests re-pointed at the async seam.
568b16122d