`record`/`record_media` do a read-modify-write of the JSON index ending in
`atomic_json_write`/`os.replace`, and every coroutine on the WhatsApp Cloud,
WhatsApp bridge and Telegram send/inbound paths called them inline on the
loop thread, stalling the whole gateway for a filesystem write nothing
awaits. Add `record_async`/`record_media_async` as thin
`asyncio.to_thread` wrappers (same precedent as
gateway/channel_directory.py) and await them from the seven coroutine call
sites; the sync functions stay for sync callers. The write completes before
the await returns, so lookup-after-send behaviour is unchanged.
Salvaged from #118883 by @Kyzcreig; re-shaped onto asyncio.to_thread (no
writer thread, no in-memory shadow, no queue), plus the missed
plugins/platforms/whatsapp/adapter.py record_media site.
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