The adapter-level intake gate (_is_dm_allowed / _is_group_allowed, reached
via _should_process_message) did a raw set-membership check against the
configured allowlist. WhatsApp now delivers inbound DM senders in LID form
(<id>@lid) while operators configure allowlists with phone numbers, so the
check never matched and every DM from an allowed contact was silently
dropped before the gateway authz layer ran.
Route both gates through the existing gateway.whatsapp_identity.
expand_whatsapp_aliases helper (already used by gateway authz and session
keys), which walks the bridge's lid-mapping-*.json session files. Phone and
LID forms now resolve to each other in both directions; exact JID matches,
wildcard, disabled/open policies, and empty-allowlist fail-closed behavior
are all preserved.
Fixes#14486
caf4dcc7ad