to:[] array /send path skips rule-1a origin_aro membership check

Pre-existing (NOT introduced by VENUS-222). The multi-recipient to:[] array /send path does not enforce the rule-1a origin_aro membership check that deliverMessage applies: a non-member can tag any origin_aro lane via the array form. Flagged by coder-llmmsgsrv-cc during VENUS-222 (the reroute carries its own 1a mirror because the surrounding array path has none). Fix: mirror deliverMessage's 1a membership guard into the array path so both /send paths enforce identically. Audit reviews.