Salvage of #2794 by @CharmingGroot, ported to the relocated
plugins/platforms/email/adapter.py:
- Guard raw_email = msg_data[0][1] against IndexError/TypeError and
non-bytes payloads. UIDs are added to _seen_uids before fetch, so an
exception mid-batch permanently skipped every remaining message in
the batch — now the bad message is logged and skipped instead.
- Message-ID domain generation falls back to 'localhost' when
EMAIL_ADDRESS lacks '@' (now via a shared _message_id_domain() helper
covering all 3 send paths; the PR fixed 2 of 3).
88bd1c01e1