The receive-path handler was ~165 lines deep into nested DM/group policy
checks, buffer mutations, mention stripping, attachment downloads, and
final bus forwarding. Pull the policy gate out into _check_inbound_policy
(returns (allow, chat_id), still appends to the group buffer once allowed)
and the text+media construction into _assemble_inbound_content. The
top-level method now reads as orchestration only.
Add TestCheckInboundPolicy that exercises the helper directly across the
DM/group policy permutations, including the buffer side effect, so the
new seam is locked in.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
7caf492ae2